Sulfonyldiazomethanes, photoacid generators, resist compositions, and patterning process

ABSTRACT

A chemical amplification type resist composition comprising a specific benzenesulfonyldiazomethane containing a long-chain alkoxyl group at the 2-position on benzene ring has many advantages including improved resolution, improved focus latitude, minimized line width variation or shape degradation even on long-term PED, minimized debris left after coating, development and peeling, and improved pattern profile after development and is thus suited for microfabrication.

This Nonprovisional application claims priority under 35 U.S.C. § 119(a)on Patent Application No(s) 2003-035077 filed in JAPAN on Feb. 13, 2003,the entire contents of which are hereby incorporated by reference.

This invention relates to novel sulfonyldiazomethane compounds,photoacid generators for resist compositions, resist compositionscomprising the photoacid generators, and a patterning process using thesame. The resist compositions, especially chemical amplification typeresist compositions are sensitive to such radiation as UV, deep UV,electron beams, x-rays, excimer laser beams, γ-rays, and synchrotronradiation and suitable for the microfabrication of integrated circuits.

BACKGROUND OF THE INVENTION

While a number of efforts are currently being made to achieve a finerpattern rule in the drive for higher integration and operating speeds inLSI devices, deep-ultraviolet lithography is thought to hold particularpromise as the next generation in microfabrication technology.

One technology that has attracted a good deal of attention recentlyutilizes as the deep UV light source a high-intensity KrF excimer laser,especially an ArF excimer laser featuring a shorter wavelength. There isa desire to have a microfabrication technique of finer definition bycombining exposure light of shorter wavelength with a resist materialhaving a higher resolution.

In this regard, the recently developed, acid-catalyzed, chemicalamplification type resist materials are expected to comply with the deepUV lithography because of their many advantages including highsensitivity, resolution and dry etching resistance. The chemicalamplification type resist materials include positive working materialsthat leave the unexposed areas with the exposed areas removed andnegative working materials that leave the exposed areas with theunexposed areas removed.

In chemical amplification type, positive working, resist compositions tobe developed with alkaline developers, an alkali-soluble phenol or aresin and/or compound in which carboxylic acid is partially or entirelyprotected with acid-labile protective groups (acid labile groups) iscatalytically decomposed by an acid which is generated upon exposure, tothereby generate the phenol or carboxylic acid in the exposed area whichis removed by an alkaline developer. Also, in similar negative workingresist compositions, an alkali-soluble phenol or a resin and/or compoundhaving carboxylic acid and a compound (crosslinking agent) capable ofbonding or crosslinking the resin or compound under the action of anacid are crosslinked with an acid which is generated upon exposurewhereby the exposed area is converted to be insoluble in an alkalinedeveloper and the unexposed area is removed by the alkaline developer.

On use of the chemical amplification type, positive working, resistcompositions, a resist film is formed by dissolving a resin having acidlabile groups as a binder and a compound capable of generating an acidupon exposure to radiation (to be referred to as photoacid generator) ina solvent, applying the resist solution onto a substrate by a variety ofmethods, and evaporating off the solvent optionally by heating. Theresist film is then exposed to radiation, for example, deep UV through amask of a predetermined pattern. This is optionally followed bypost-exposure baking (PEB) for promoting acid-catalyzed reaction. Theexposed resist film is developed with an aqueous alkaline developer forremoving the exposed area of the resist film, obtaining a positivepattern profile. The substrate is then etched by any desired technique.Finally the remaining resist film is removed by dissolution in a removersolution or ashing, leaving the substrate having the desired patternprofile.

The chemical amplification type, positive working, resist compositionsadapted for KrF excimer lasers generally use a phenolic resin, forexample, polyhydroxystyrene in which some or all of the hydrogen atomsof phenolic hydroxyl groups are protected with acid labile protectivegroups. Iodonium salts, sulfonium salts, and bissulfonyldiazomethanecompounds are typically used as the photoacid generator. If necessary,there are added additives, for example, a dissolution inhibiting orpromoting compound in the form of a carboxylic acid and/or phenolderivative having a molecular weight of up to 3,000 in which some or allof the hydrogen atoms of carboxylic acid and/or phenolic hydroxyl groupsare protected with acid labile groups, a carboxylic acid compound forimproving dissolution characteristics, a basic compound for improvingcontrast, and a surfactant for improving coating characteristics.

Bissulfonyldiazomethanes as shown below are advantageously used as thephotoacid generator in chemical amplification type resist compositions,especially chemical amplification type, positive working, resistcompositions adapted for KrF excimer lasers because they provide a highsensitivity and resolution and eliminate poor compatibility with resinsand poor solubility in resist solvents as found with the sulfonium andiodonium salt photoacid generators.

Although these photoacid generators are highly lipophilic and highlysoluble in resist solvents, they have poor affinity to or solubility indevelopers so that upon development and/or resist removal, the photoacidgenerators can be left on the substrate as insoluble matter (consistingof the photoacid generator or a mixture thereof with the resin).

For example, upon development, the resist material which has pooraffinity to or solubility in a developer deposits on developed spaces inthe exposed area or on lines in the unexposed area as foreign matter.

JP-A 3-103854 discloses bis(4-methoxyphenylsulfonyl)diazomethane as aphotoacid generator having a methoxy group introduced therein. As longas we confirmed, the methoxy group is not fully effective. The photoacidgenerator is often left on the substrate as insoluble matter (consistingof the photoacid generator or a mixture thereof with the resin) upondevelopment and/or resist film removal.

If unsubstituted bis(phenylsulfonyl)diazomethane orbis(cyclohexylsulfonyl)diazomethane having alkyl groups instead of arylgroups is used in a resist material as the photoacid generator forreducing lipophilic property, resolution is deteriorated. If it is addedin large amounts, the problem of insoluble matter upon developmentand/or resist film removal remains unsolved.

Aside from the countermeasure for foreign matter, JP-A 10-90884discloses to introduce such an acid labile group as t-butoxycarbonyloxy,ethoxyethyl or tetrahydropyranyl into disulfonediazomethane for thepurpose of improving the contrast of positive resist material. Weempirically found that these compounds are unstable and ineffective foreliminating the foreign matter upon development and resist film removal.

Searching for a countermeasure to the foreign matter problem, we alreadysynthesized sulfonyldiazomethanes having an acyl group (e.g., acetyl) ormethanesulfonyl group introduced therein and found that they were usefulas the photoacid generator in chemical amplification type resistcomposition. Since these arylsulfonyldiazomethanes having an acyl groupor methanesulfonyl group introduced therein lack stability under basicconditions during their synthesis, the yield of diazo formation issometimes low. See JP-A 2001-055373 and JP-A 2001-106669.

It is known from JP-A 8-123032 to use two or more photoacid generatorsin a resist material. JP-A 11-72921 discloses the use of aradiation-sensitive acid generator comprising in admixture a compoundwhich generates a sulfonic acid having at least three fluorine atomsupon exposure to radiation and a compound which generates a fluorineatom-free sulfonic acid upon exposure to radiation, thereby improvingresolution without inviting nano-edge roughness and film surfaceroughening. JP-A 11-38604 describes that a resist composition comprisingan asymmetric bissulfonyldiazomethane such as a bissulfonyldiazomethanehaving alkylsulfonyl and arylsulfonyl groups or abissulfonyldiazomethane having arylsulfonyl and alkoxy-substitutedarylsulfonyl groups and a polyhydroxystyrene derivative having acidlabile groups as the polymer has a resolution at least comparable toprior art compositions, a sufficient sensitivity and significantlyimproved heat resistance. However, we empirically found that theseresist compositions are unsatisfactory in resolution and in the effectof eliminating the foreign matter on the pattern upon development. Fromthe synthetic and industrial standpoints, it is difficult to obtainbilaterally asymmetric bissulfonyldiazomethanes.

Aside from the above-discussed problem of insoluble matter upondevelopment and/or removal, there is also a problem that the patternprofile often changes when the period from exposure to post-exposurebaking (PEB) is prolonged, which is known as post-exposure delay (PED).Such changes frequently reveal as a slimming of the line width ofunexposed areas in the case of chemical amplification type positiveresist compositions using acetal and analogous acid labile groups, andas a thickening of the line width of unexposed areas in the case ofchemical amplification type positive resist compositions usingtert-butoxycarbonyl (t-BOC) and analogous acid labile groups. Since theperiod from exposure to PEB is often prolonged for the operationalreason, there is a desire to have a stable resist composition which isfree from such changes, that is, has PED stability.

In some resist processes, baking is performed at far higher temperatures(e.g., 130° C.) than the customary baking temperature of 120° C. orbelow as disclosed in JP-A 6-266112. In this case, thebissulfonyldiazomethanes shown above by structural formulae can bethermally decomposed to generate acids due to their low heat resistanceso that acidolysis takes place everywhere regardless of whether theareas are exposed or unexposed, failing in pattern formation.

The solubility of photosensitive agents or photoacid generators was theproblem from the age when quinonediazide photosensitive agents were usedin non-chemical amplification type resist materials. Specificconsiderations include the solubility of photoacid generators in resistsolvents, the compatibility of photoacid generators with resins, thesolubility (or affinity) of photo-decomposed products after exposure andPEB and non-decomposed compound (photoacid generator) in a developer,and the solubility of the photoacid generator and photo-decomposedproducts thereof in a remover solvent upon resist removal or peeling. Ifthese factors are poor, there can occur problems including precipitationof the photoacid generator during storage, difficulty of filtration,uneven coating, striation, abnormal resist sensitivity, and foreignmatter, left-over and staining on the pattern and in spaces afterdevelopment.

The photoacid generator in resist material is required to meet a fullyhigh solubility in (or compatibility with) a resist solvent and a resin,good storage stability, non-toxicity, effective coating, a well-definedpattern profile, PED stability, no foreign matter left during patternformation after development and upon resist removal, and heatresistance. The conventional photoacid generators, especiallydiazodisulfone photoacid generators do not meet all of theserequirements.

As the pattern of integrated circuits becomes finer in these days, ahigher resolution is, of course, required, and the problem of foreignmatter after development and resist removal becomes more serious.

SUMMARY OF THE INVENTION

An object of the invention is to provide a novel sulfonyldiazomethanefor use in a resist composition, especially of the chemicalamplification type, such that the resist composition minimizes theforeign matter left after coating, development and resist removal, hassatisfactory heat resistance, and ensures a well-defined pattern profileafter development. Another object of the invention is to provide aphotoacid generator for resist compositions, a resist compositioncomprising the photoacid generator, and a patterning process using thesame.

We have found that by using a sulfonyldiazomethane compound of thegeneral formula (1), especially formula (1a), to be defined below, asthe photoacid generator in a resist composition, there are achieved anumber of advantages including dissolution, storage stability, effectivecoating, minimized line width variation or shape degradation duringlong-term PED, minimized foreign matter left after coating, developmentand resist removal, satisfactory heat resistance, a well-defined patternprofile after development, and a high resolution enough formicrofabrication, especially by deep UV lithography. Better results areobtained when a sulfonyldiazomethane compound of the formula (1),especially formula (1a), is used as the photoacid generator in achemical amplification type resist composition, typically chemicalamplification positive type resist composition comprising a resin whichchanges its solubility in an alkaline developer under the action of anacid as a result of scission of C—O—C linkages. The composition exertsits effect to the maximum extent when processed by deep UV lithography.

In a first aspect, the invention provides a sulfonyldiazomethanecompound having the following general formula (1).

Herein R is each independently a substituted or unsubstituted straight,branched or cyclic alkyl group of 1 to 4 carbon atoms, G is SO₂ or CO,R³ is a substituted or unsubstituted straight, branched or cyclic alkylgroup of 1 to 10 carbon atoms or a substituted or unsubstituted arylgroup of 6 to 14 carbon atoms, p is 1 or 2, q is 0 or 1, satisfyingp+q=2, m is an integer of 3 to 11, and k is an integer of 0 to 4, withthe proviso that in the event k is at least 1, at least one of Rassociated with k may bond with the R at the 4-position to form a cyclicstructure with the carbon atoms on the benzene ring to which these R'sare attached, and then, these two R's bond together to form an alkylenegroup of 3 to 4 carbon atoms.

Typical sulfonyldiazomethane compounds have the following generalformula (1a).

wherein R is each independently a substituted or unsubstituted straight,branched or cyclic alkyl group of 1 to 4 carbon atoms, and m is aninteger of 3 to 11.

In a second aspect, the invention provides a photoacid generator for achemical amplification type resist composition comprising thesulfonyldiazomethane compound of formula (1) or (1a).

In a third aspect, the invention provides a chemical amplification typeresist composition comprising (A) a resin which changes its solubilityin an alkaline developer under the action of an acid, (B) thesulfonyldiazomethane compound of formula (1) or (1a) which generates anacid upon exposure to radiation, and optionally, (C) a compound capableof generating an acid upon exposure to radiation, other than component(B). The resist composition may further contain (D) a basic compound,(E) an organic acid derivative, and an organic solvent.

The resin (A) typically has such substituent groups having C—O—Clinkages that the solubility in an alkaline developer changes as aresult of scission of the C—O—C linkages under the action of an acid.

In a preferred embodiment, the resin (A) is a polymer containingphenolic hydroxyl groups in which hydrogen atoms of the phenolichydroxyl groups are substituted with acid labile groups of one or moretypes in a proportion of more than 0 mol % to 80 mol % on the average ofthe entire hydrogen atoms of the phenolic hydroxyl groups, the polymerhaving a weight average molecular weight of 3,000 to 100,000.

More preferably, the resin (A) is a polymer comprising recurring unitsof the following general formula (2a):

wherein R⁴ is hydrogen or methyl, R⁵ is a straight, branched or cyclicalkyl group of 1 to 8 carbon atoms, x is 0 or a positive integer, y is apositive integer, satisfying x+y≦5, R⁶ is an acid labile group, S and Tare positive integers, satisfying 0<T/(S+T)≦0.8, wherein the polymercontains units in which hydrogen atoms of phenolic hydroxyl groups arepartially substituted with acid labile groups of one or more types, aproportion of the acid labile group-bearing units is on the average frommore than 0 mol % to 80 mol % based on the entire polymer, and thepolymer has a weight average molecular weight of 3,000 to 100,000.

In another preferred embodiment, the resin (A) is a polymer comprisingrecurring units of the following general formula (2a′):

wherein R⁴ is hydrogen or methyl, R⁵ is a straight, branched or cyclicalkyl group of 1 to 8 carbon atoms, R⁶ is an acid labile group, R^(6a)is hydrogen or an acid labile group, at least some of R^(6a) being acidlabile groups, x is 0 or a positive integer, y is a positive integer,satisfying x+y≦5, M and N are positive integers, L is 0 or a positiveinteger, satisfying 0<N/(M+N+L)≦0.5 and 0<(N+L)/(M+N+L)≦0.8, wherein thepolymer contains on the average from more than 0 mol % to 50 mol % ofthose units derived from acrylate and methacrylate, and also contains onthe average from more than 0 mol % to 80 mol % of acid labilegroup-bearing units, based on the entire polymer, and the polymer has aweight average molecular weight of 3,000 to 100,000.

In a further preferred embodiment, the resin (A) is a polymer comprisingrecurring units of the following general formula (2a″):

wherein R⁴ is hydrogen or methyl, R⁵ is a straight, branched or cyclicalkyl group of 1 to 8 carbon atoms, R⁶ is an acid labile group, R^(6a)is hydrogen or an acid labile group, at least some of R^(6a) being acidlabile groups, x is 0 or a positive integer, y is a positive integer,satisfying x+y≦5, yy is 0 or a positive integer, satisfying x+yy≦5, Aand B are positive integers, C, D and E each are 0 or a positiveinteger, satisfying 0<(B+E)/(A+B+C+D+E)≦0.5 and0<(C+D+E)/(A+B+C+D+E)≦0.8, wherein the polymer contains on the averagefrom more than 0 mol % to 50 mol % of those units derived from indeneand/or substituted indene, and also contains on the average from morethan 0 mol % to 80 mol % of acid labile group-bearing units, based onthe entire polymer, and the polymer has a weight average molecularweight of 3,000 to 100,000.

In these preferred embodiments, the acid labile group is selected fromthe class consisting of groups of the following general formulae (4) to(7), tertiary alkyl groups of 4 to 20 carbon atoms, trialkylsilyl groupswhose alkyl moieties each have 1 to 6 carbon atoms, oxoalkyl groups of 4to 20 carbon atoms, and aryl-substituted alkyl groups of 7 to 20 carbonatoms.

Herein R¹⁰ and R¹¹ each are hydrogen or a straight, branched or cyclicalkyl having 1 to 18 carbon atoms, and R¹² is a monovalent hydrocarbongroup of 1 to 18 carbon atoms which may contain a heteroatom, a pair ofR¹⁰ and R¹¹, R¹⁰ and R¹², or R¹¹ and R¹² may together form a ring, withthe proviso that R¹⁰, R¹¹, and R¹² each are a straight or branchedalkylene of 1 to 18 carbon atoms when they form a ring,

R¹³ is a tertiary alkyl group of 4 to 20 carbon atoms, a trialkysilylgroup in which each of the alkyls has 1 to 6 carbon atoms, an oxoalkylgroup of 4 to 20 carbon atoms, or a group of the formula (4), z is aninteger of 0 to 6,

R¹⁴ is a straight, branched or cyclic alkyl group of 1 to 8 carbon atomsor an aryl group of 6 to 20 carbon atoms which may be substituted, h is0 or 1, i is 0, 1, 2 or 3, satisfying 2h+i=2 or 3,

R¹⁵ is a straight, branched or cyclic alkyl group of 1 to 8 carbon atomsor an aryl group of 6 to 20 carbon atoms which may be substituted, R¹⁶to R²⁵ are each independently hydrogen or a monovalent hydrocarbon groupof 1 to 15 carbon atoms which may contain a heteroatom, any two of R¹⁶to R²⁵, taken together, may form a ring, each of the ring-forming two ofR¹⁶ to R²⁵ is a divalent hydrocarbon group of 1 to 15 carbon atoms whichmay contain a heteroatom, or two of R¹⁶ to R²⁵ which are attached toadjoining carbon atoms may bond together directly to form a double bond.

Preferably, the resist composition contains a propylene glycol alkylether acetate, an alkyl lactate or a mixture thereof as the organicsolvent.

Also contemplated herein is a process for forming a pattern, comprisingthe steps of applying the resist composition onto a substrate to form acoating; heat treating the coating and exposing the coating to highenergy radiation with a wavelength of up to 300 nm or electron beamthrough a photomask; optionally heat treating the exposed coating, anddeveloping the coating with a developer.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Sulfonyldiazomethane

In the first aspect of the invention, novel sulfonyldiazomethanecompounds having a long-chain alkoxyl group are provided. They arerepresented by the general formula (1).

Herein R is each independently a substituted or unsubstituted straight,branched or cyclic alkyl group of 1 to 4 carbon atoms. G is SO₂ or CO.R³ is a substituted or unsubstituted straight, branched or cyclic alkylgroup of 1 to 10 carbon atoms or a substituted or unsubstituted arylgroup of 6 to 14 carbon atoms. The subscript p is 1 or 2, q is 0 or 1,satisfying p+q=2, m is an integer of 3 to 11, and k is an integer of 0to 4. In the event k is at least 1, at least one of R associated with kmay bond with the R at the 4-position to form a cyclic structure withthe carbon atoms on the benzene ring to which these R's are attached,and then, these two R's bond together to form an alkylene group of 3 or4 carbon atoms.

Preferred among the sulfonyldiazomethane compounds of formula (1) aresulfonyldiazomethane compounds having long-chain alkoxyl groups of thefollowing general formula (1a).

Herein R is each independently a substituted or unsubstituted straight,branched or cyclic alkyl group of 1 to 4 carbon atoms, and m is aninteger of 3 to 11.

In formulae (1) and (1a), R may be the same or different and stands forsubstituted or unsubstituted, straight, branched or cyclic alkyl groupsof 1 to 4 carbon atoms, for example, methyl, ethyl, n-propyl,sec-propyl, cyclopropyl, n-butyl, sec-butyl, iso-butyl, tert-butyl,2-methoxyethyl and trifluoromethyl. A plurality of R groups may bondtogether to form a cyclic structure. In one example, a tetramethylene ortrimethylene group is attached at the 4,5-positions relative to thesulfonyl to form a cyclic structure. Of these, methyl, ethyl, n-propyl,isopropyl and tert-butyl are preferred, with tert-butyl being mostpreferred.

The subscript k is an integer of 0 to 3, and preferably 0, 1 or 2. Thesubstitution position of R associated with k is arbitrary.

R³ stands for substituted or unsubstituted, straight, branched or cyclicalkyl groups of 1 to 10 carbon atoms or substituted or unsubstitutedaryl groups of 6 to 14 carbon atoms. Illustrative, non-limiting,examples of the straight, branched or cyclic alkyl groups includemethyl, ethyl, n-propyl, sec-propyl, n-butyl, sec-butyl, iso-butyl,tert-butyl, n-pentyl, sec-pentyl, cyclopentyl, n-hexyl, and cyclohexyl.Illustrative, non-limiting, examples of the substituted or unsubstitutedaryl groups include phenyl, 4-methylphenyl, 4-ethylphenyl,4-methoxyphenyl, 4-tert-butylphenyl, 4-tert-butoxyphenyl,4-cyclohexylphenyl, 4-cyclohexyloxyphenyl, 2,4-dimethylphenyl,2,4,6-trimethylphenyl, 2,4,6-triisopropylphenyl, 1-naphthyl and2-naphthyl. Of these, tert-butyl, cyclohexyl, 4-methylphenyl,2,4-dimethylphenyl and 4-tert-butylphenyl are preferred. G stands forSO₂ or CO. SO₂ is preferred.

It is noted that the substituted alkyl groups include halogenated alkylgroups (e.g., chloro or fluoro-substituted ones), carbonyl-containingalkyl groups, and alkyl groups having a carbonyl group protected with anacetal (ketal). The substituted aryl groups include halogenated arylgroups (e.g., chloro or fluoro-substituted ones) and straight, branchedor cyclic alkoxy group-substituted aryl groups. Specific examplesinclude 2,4-difluorophenyl, 4-trifluoromethylphenyl, and groups of thefollowing formulae.

The subscript p is equal to 1 or 2, q is equal to 0 or 1, satisfyingp+q=2. The subscript m is an integer of 3 to 11, preferably an integerof 3 to 6 as long as the boiling point of intermediate reactants isconcerned.

The sulfonyldiazomethane compounds can be synthesized by the followingmethod although the synthesis method is not limited thereto.

Reference is first made to a sulfonyldiazomethane compound of formula(1) wherein p=2, that is, a symmetric bissulfonyldiazomethane compound.It is desirably synthesized by condensing a substituted thiophenol withdichloromethane under basic conditions as disclosed in JP-A 3-103854.More specifically, a long chain alkoxyl-containing thiophenol such as2-(n-hexyloxy)-5-tert-butylthiophenol is condensed with dichloromethanein an alcohol solvent such as methanol or ethanol in the presence of abase such as sodium hydroxide or potassium hydroxide, obtaining aformaldehyde bis(alkoxyphenylthio)acetal.

Herein, R, m and k are as defined above.

Alternatively, a substituted thiophenol is condensed with a formaldehyde(typically paraformaldehyde) under acidic conditions such as sulfuricacid or trifluoromethanesulfonic acid.

In the case of p=1, that is, an asymmetric sulfonyldiazomethanecompound, reaction is effected between a halomethyl thioether and analkoxy-substituted thiophenol. In the case ofsulfonylcarbonyldiazomethane, reaction is conducted between anα-halomethylketone and an alkoxy-substituted thiophenol. The halomethylthioether can be prepared from a corresponding thiol, formaldehyde andhydrogen chloride (see J. Am. Chem. Soc., 86, 4383 (1964), J. Am. Chem.Soc., 67, 655 (1945), and U.S. Pat. No. 2,354,229).

Herein, R, R³, m and k are as defined above, and X is a halogen atom.

Further, the product is oxidized with an oxidant such as aqueoushydrogen peroxide in the presence of sodium tungstate etc. as describedin JP-A 4-211258, yielding a corresponding sulfonylmethane.

Herein, R, R³, m and k are as defined above.

This product is reacted with p-toluenesulfonylazide,p-dodecylbenzenesulfonylazide or p-acetamidobenzenesulfonylazide underbasic conditions into a diazo form, yielding the endsulfonyldiazomethane.

Herein, R, R³, m and k are as defined above.

It is noted that the synthesis of alkoxy-substituted thiophenols is notcritical. They can be synthesized by converting an alkoxybenzene withchlorosulfuric acid, sulfuric acid/acetic anhydride or the like to asubstituted benzene sulfonic acid, then converting it withchlorosulfuric acid, thionyl chloride or the like to a substitutedbenzene sulfonyl chloride, and reducing it with aluminum lithiumhydride, hydrochloric acid/zinc or the like as shown below.

Herein R, m and k are as defined above.

Alternatively, a halogenated alkoxybenzene is treated with metallicmagnesium to form a Grignard reagent, which is reacted with sulfur andacidified. See Romeo B. Wagner and Harry D. Zook, Synthetic OrganicChemistry, John Wiley & Sons, Inc., 1965, 778–781.

Herein R, m and k are as defined above, and X is a halogen atom.

The halogenated alkoxybenzene can be synthesized by reacting a phenolderivative with CH₃(CH₂)_(m)X under basic conditions, followed byreaction with halogen such as bromine. Exemplary of suitable phenolderivatives are p-cresol, 4-ethylphenol, 4-isopropylphenol,4-tert-butylphenol, 4-(2-methoxyethyl)phenol,5,6,7,8-tetrahydro-2-naphthol, and 5-indanol, with 4-tert-butylphenolbeing preferred.

Herein R, m and k are as defined above, and X is a halogen atom.

Examples of the sulfonyldiazomethanes of formulae (1) and (1a) includethose of the following structures, but are not limited thereto.

It is noted that m is an integer of 3 to 11.

The sulfonyldiazomethane compounds of formula (1) or (1a) are useful asthe photoacid generator in resist materials, especially chemicalamplification type resist materials, which are sensitive to radiationsuch as ultraviolet, deep ultraviolet, electron beams, x-rays, excimerlaser light, γ-rays, and synchrotron radiation, for use in themicrofabrication of integrated circuits.

Resist Composition

The resist compositions of the invention contain one or more of thesulfonyldiazomethane compounds of formula (1) or (1a). The resistcompositions may be either positive or negative working although theyare preferably of the chemical amplification type. The resistcompositions of the invention include a variety of embodiments,

1) a chemically amplified positive working resist composition comprising(A) a resin which changes its solubility in an alkaline developer underthe action of an acid, (B) a sulfonyldiazomethane compound capable ofgenerating an acid upon exposure to radiation represented by the generalformula (1) or (1a), and (F) an organic solvent;

2) a chemically amplified positive working resist composition of 1)further comprising (C) a photoacid generator capable of generating anacid upon exposure to radiation other than component (B);

3) a chemically amplified positive working resist composition of 1) or2) further comprising (D) a basic compound;

4) a chemically amplified positive working resist composition of 1) to3) further comprising (E) an organic acid derivative;

5) a chemically amplified positive working resist composition of 1) to4) further comprising (G) a compound with a molecular weight of up to3,000 which changes its solubility in an alkaline developer under theaction of an acid;

6) a chemically amplified negative working resist composition comprising(B) a sulfonyldiazomethane compound capable of generating an acid uponexposure to radiation represented by the general formula (1) or (1a),(F) an organic solvent, (H) an alkali-soluble resin, and (I) an acidcrosslinking agent capable of forming a crosslinked structure under theaction of an acid;

7) a chemically amplified negative working resist composition of 6)further comprising (C) another photoacid generator;

8) a chemically amplified negative working resist composition of 6) or7) further comprising (D) a basic compound; and

9) a chemically amplified negative working resist composition of 6) to8) further comprising (J) an alkali soluble compound having a molecularweight of up to 2,500; but not limited thereto.

Now the respective components are described in detail.

Component (A)

Component (A) is a resin which changes its solubility in an alkalinedeveloper solution under the action of an acid. It is preferably, thoughnot limited to, an alkali-soluble resin having phenolic hydroxyl and/orcarboxyl groups in which some or all of the phenolic hydroxyl and/orcarboxyl groups are protected with acid-labile protective groups havinga C—O—C linkage.

The alkali-soluble resins having phenolic hydroxyl and/or carboxylgroups include homopolymers and copolymers of p-hydroxystyrene,m-hydroxystyrene, α-methyl-p-hydroxystyrene, 4-hydroxy-2-methylstyrene,4-hydroxy-3-methylstyrene, hydroxyindene, methacrylic acid and acrylicacid, and copolymers having a carboxylic derivative or diphenyl ethyleneintroduced at the terminus of the foregoing polymers.

Also included are copolymers in which units free of alkali-soluble sitessuch as styrene, α-methylstyrene, acrylate, methacrylate, hydrogenatedhydroxystyrene, maleic anhydride, maleimide, substituted orunsubstituted indene are introduced in addition to the above-describedunits in such a proportion that the solubility in an alkaline developermay not be extremely reduced. Substituents on the acrylates andmethacrylates may be any of the substituents which do not undergoacidolysis. Exemplary substituents are straight, branched or cyclic C₁₋₈alkyl groups and aromatic groups such as aryl groups, but not limitedthereto.

Examples of the alkali-soluble resins or polymers are given below. Thesepolymers may also be used as the material from which the resin (A) whichchanges its solubility in an alkaline developer under the action of anacid is prepared and as the alkali-soluble resin which serves ascomponent (H) to be described later. Examples includepoly(p-hydroxystyrene), poly(m-hydroxystyrene),poly(4-hydroxy-2-methylstyrene), poly(4-hydroxy-3-methylstyrene),poly(α-methyl-p-hydroxystyrene), partially hydrogenated p-hydroxystyrenecopolymers, p-hydroxystyrene-α-methyl-p-hydroxystyrene copolymers,p-hydroxystyrene-α-methylstyrene copolymers, p-hydroxystyrene-styrenecopolymers, p-hydroxystyrene-m-hydroxystyrene copolymers,p-hydroxystyrene-styrene copolymers, p-hydroxystyrene-indene copolymers,p-hydroxystyrene-acrylic acid copolymers, p-hydroxystyrene-methacrylicacid copolymers, p-hydroxystyrene-methyl acrylate copolymers,p-hydroxystyrene-acrylic acid-methyl methacrylate copolymers,p-hydroxystyrene-methyl methacrylate copolymers,p-hydroxystyrene-methacrylic acid-methyl methacrylate copolymers,poly(methacrylic acid), poly(acrylic acid), acrylic acid-methyl acrylatecopolymers, methacrylic acid-methyl methacrylate copolymers, acrylicacid-maleimide copolymers, methacrylic acid-maleimide copolymers,p-hydroxystyrene-acrylic acid-maleimide copolymers, andp-hydroxystyrene-methacrylic acid-maleimide copolymers, but are notlimited to these combinations.

Preferred are poly(p-hydroxystyrene), partially hydrogenatedp-hydroxystyrene copolymers, p-hydroxystyrene-styrene copolymers,p-hydroxystyrene-indene copolymers, p-hydroxystyrene-acrylic acidcopolymers, and p-hydroxystyrene-methacrylic acid copolymers.

Alkali-soluble resins comprising units of the following formula (2),(2′) or (2″) are especially preferred.

Herein R⁴ is hydrogen or methyl, R⁵ is a straight, branched or cyclicalkyl group of 1 to 8 carbon atoms, x is 0 or a positive integer, y is apositive integer, satisfying x+y≦5, M and N are positive integers,satisfying 0<N/(M+N)≦0.5, and A and B are positive integers, and C is 0or a positive integer, satisfying 0<B/(A+B+C)≦0.5.

The polymer of formula (2″) can be synthesized, for example, byeffecting thermal polymerization of an acetoxystyrene monomer, atertiary alkyl(meth)acrylate monomer and an indene monomer in an organicsolvent in the presence of a radical initiator, and subjecting theresulting polymer to alkaline hydrolysis in an organic solvent fordeblocking the acetoxy group, for thereby forming a ternary copolymer ofhydroxystyrene, tertiary alkyl(meth)acrylate and indene. The organicsolvent used during polymerization is exemplified by toluene, benzene,tetrahydrofuran, diethyl ether and dioxane. Exemplary polymerizationinitiators include 2,2′-azobisisobutyronitrile,2,2′-azobis(2,4-dimethylvaleronitrile),dimethyl-2,2-azobis(2-methylpropionate), benzoyl peroxide, and lauroylperoxide. Polymerization is preferably effected while heating at 50 to80° C. The reaction time is usually about 2 to 100 hours, preferablyabout 5 to 20 hours. Aqueous ammonia, triethylamine or the like may beused as the base for the alkaline hydrolysis. For the alkalinehydrolysis, the temperature is usually −20° C. to 100° C., preferably 0°C. to 60° C., and the time is about 0.2 to 100 hours, preferably about0.5 to 20 hours.

Also included are polymers having the dendritic or hyperbranched polymerstructure of formula (2″′) below.

Herein ZZ is a divalent organic group selected from among CH₂, CH(OH),CR⁵(OH), C═O and C(OR⁵)(OH) or a trivalent organic group represented by—C(OH)═. Subscript F, which may be identical or different, is a positiveinteger, and H is a positive integer, satisfying 0.001≦H/(H+F)≦0.1, andXX is 1 or 2. R⁴, R⁵, x and y are as defined above.

The dendritic or hyperbranched polymer of phenol derivative can besynthesized by effecting living anion polymerization of a polymerizablemonomer such as 4-tert-butoxystyrene and reacting a branching monomersuch as chloromethylstyrene as appropriate during the living anionpolymerization. For the detail of synthesis, reference is made to JP-A2000-344836.

The alkali-soluble resins or polymers should preferably have a weightaverage molecular weight (Mw) of 3,000 to 100,000. Many polymers with Mwof less than 3,000 do not perform well and are poor in heat resistanceand film formation. Many polymers with Mw of more than 100,000 give riseto a problem with respect to dissolution in the resist solvent anddeveloper. The polymer should also preferably have a dispersity (Mw/Mn)of up to 3.5, and more preferably up to 1.5. With a dispersity of morethan 3.5, resolution is low in many cases. Although the preparationmethod is not critical, a poly(p-hydroxystyrene) or similar polymer witha low dispersity or narrow dispersion can be synthesized by living anionpolymerization.

In the resist composition using the sulfonyldiazomethane of formula (1),a resin having such substituent groups with C—O—C linkages (acid labilegroups) that the solubility in an alkaline developer changes as a resultof severing of the C—O—C linkages under the action of an acid,especially an alkali-soluble resin as mentioned above is preferably usedas component (A). Especially preferred is a polymer comprising recurringunits of the above formula (2) and containing phenolic hydroxyl groupsin which hydrogen atoms of the phenolic hydroxyl groups are substitutedwith acid labile groups of one or more types in a proportion of morethan 0 molt to 80 molt on the average of the entire hydrogen atoms ofthe phenolic hydroxyl group, the polymer having a weight averagemolecular weight of 3,000 to 100,000.

Also preferred is a polymer comprising recurring units of the aboveformula (2′), that is, a copolymer comprising p-hydroxystyrene and/orα-methyl-p-hydroxystyrene and acrylic acid and/or methacrylic acid,wherein some of the hydrogen atoms of the carboxyl groups of acrylicacid and/or methacrylic acid are substituted with acid labile groups ofone or more types, and the units derived from acrylate and/ormethacrylate are contained in a proportion of more than 0 molt to 50molt, on the average, of the copolymer, and wherein some of the hydrogenatoms of the phenolic hydroxyl groups of p-hydroxystyrene and/orα-methyl-p-hydroxystyrene may be substituted with acid labile groups ofone or more types. In the preferred copolymer, the units derived fromacrylate and/or methacrylate and the units derived from p-hydroxystyreneand/or α-methyl-p-hydroxystyrene optionally having acid labile groupssubstituted thereon are contained in a proportion of more than 0 molt to80 mol %, on the average, of the copolymer.

Alternatively, a polymer comprising recurring units of the above formula(2″), that is, a copolymer comprising p-hydroxystyrene and/orα-methyl-p-hydroxystyrene and substituted and/or unsubstituted indene,is preferred wherein some of the hydrogen atoms of the phenolic hydroxylgroups of p-hydroxystyrene and/or α-methyl-p-hydroxystyrene aresubstituted with acid labile groups of one or more types, and some ofthe hydrogen atoms of the carboxyl groups of acrylic acid and/ormethacrylic acid are substituted with acid labile groups of one or moretypes. Where the substituted indene has hydroxyl groups, some of thehydrogen atoms of these hydroxyl groups may be substituted with acidlabile groups of one or more types. In the preferred copolymer, theunits derived from p-hydroxystyrene and/or α-methyl-p-hydroxystyrenehaving acid labile groups substituted thereon, the units derived fromacrylic acid and/or methacrylic acid having acid labile groupssubstituted thereon, and the units derived from indene having acidlabile groups substituted thereon are contained in a proportion of morethan 0 molt to 80 molt, on the average, of the copolymer.

Exemplary and preferred such polymers are polymers or high molecularweight compounds comprising recurring units represented by the followinggeneral formula (2a), (2a′) or (2a″) and having a weight averagemolecular weight of 3,000 to 100,000.

Herein, R⁴ is hydrogen or methyl. R⁵ is a straight, branched or cyclicalkyl group of 1 to 8 carbon atoms. Letter x is 0 or a positive integer,and y is a positive integer, satisfying x+y≦5. R⁶ is an acid labilegroup. S and T are positive integers, satisfying 0<T/(S+T)≦0.8. R^(6a)is hydrogen or an acid labile group, at least some of the R^(6a) groupsare acid labile groups. M and N are positive integers, L is 0 or apositive integer, satisfying 0<N/(M+N+L)≦0.5 and 0<(N+L)/(M+N+L)≦0.5.The letter yy is 0 or a positive integer, satisfying x+yy≦5. A and B arepositive integers, C, D and E each are 0 or a positive integer,satisfying 0<(B+E)/(A+B+C+D+E)≦0.5 and 0<(C+D+E)/(A+B+C+D+E)≦0.8.

R⁵ stands for straight, branched or cyclic C₁₋₈ alkyl groups, forexample, methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl,tert-butyl, cyclohexyl and cyclopentyl.

With respect to the acid labile groups, where some of the phenolichydroxyl groups and some or all of the carboxyl groups in thealkali-soluble resin are protected with acid labile groups having C—O—Clinkages, the acid labile groups are selected from a variety of suchgroups. The preferred acid labile groups are groups of the followinggeneral formulae (4) to (7), tertiary alkyl groups of 4 to 20 carbonatoms, preferably 4 to 15 carbon atoms, trialkylsilyl groups whose alkylgroups each have 1 to 6 carbon atoms, oxoalkyl groups of 4 to 20 carbonatoms, or aryl-substituted alkyl groups of 7 to 20 carbon atoms.

Herein R¹⁰ and R¹¹ are independently hydrogen or straight, branched orcyclic alkyl groups of 1 to 18 carbon atoms, preferably 1 to 10 carbonatoms, for example, methyl, ethyl, propyl, isopropyl, n-butyl,sec-butyl, tert-butyl, cyclopentyl, cyclohexyl, 2-ethylhexyl andn-octyl. R¹² is a monovalent hydrocarbon group of 1 to 18 carbon atoms,preferably 1 to 10 carbon atoms, which may have a hetero atom (e.g.,oxygen atom), for example, straight, branched or cyclic alkyl groups,and such groups in which some hydrogen atoms are substituted withhydroxyl, alkoxy, oxo, amino or alkylamino groups. Illustrative examplesof the substituted alkyl groups are given below.

A pair of R¹⁰ and R¹¹, a pair of R¹⁰ and R¹², or a pair of R¹¹ and R¹²,taken together, may form a ring. Each of R¹⁰, R¹¹ and R¹² is a straightor branched alkylene group of 1 to 18 carbon atoms, preferably 1 to 10carbon atoms, when they form a ring.

R¹³ is a tertiary alkyl group of 4 to 20 carbon atoms, preferably 4 to15 carbon atoms, a trialkylsilyl group whose alkyl groups each have 1 to6 carbon atoms, an oxoalkyl group of 4 to 20 carbon atoms or a group offormula (4). Exemplary tertiary alkyl groups are tert-butyl, tert-amyl,1,1-diethylpropyl, 1-ethylcyclopentyl, 1-butylcyclopentyl,1-ethylcyclohexyl, 1-butylcyclohexyl, 1-ethyl-2-cyclopentenyl,1-ethyl-2-cyclohexenyl, 2-methyl-2-adamantyl, 2-ethyl-2-adamantyl and1-adamantyl-1-methylethyl. Exemplary trialkylsilyl groups aretrimethylsilyl, triethylsilyl, and dimethyl-tert-butylsilyl. Exemplaryoxoalkyl groups are 3-oxocyclohexyl, 4-methyl-2-oxooxan-4-yl, and5-methyl-5-oxooxolan-4-yl. Letter z is an integer of 0 to 6.

R¹⁴ is a straight, branched or cyclic alkyl group of 1 to 8 carbon atomsor substituted or unsubstituted aryl group of 6 to 20 carbon atoms.Exemplary straight, branched or cyclic alkyl groups include methyl,ethyl, propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, tert-amyl,n-pentyl, n-hexyl, cyclopentyl, cyclohexyl, cyclopentylmethyl,cyclopentylethyl, cyclohexylmethyl and cyclohexylethyl. Exemplarysubstituted or unsubstituted aryl groups include phenyl, methylphenyl,naphthyl, anthryl, phenanthryl, and pyrenyl. Letter h is equal to 0 or1, i is equal to 0, 1, 2 or 3, satisfying 2h+i=2 or 3.

R¹⁵ is a straight, branched or cyclic alkyl group of 1 to 8 carbon atomsor substituted or unsubstituted aryl group of 6 to 20 carbon atoms,examples of which are as exemplified for R¹⁴. R¹⁶ to R²⁵ areindependently hydrogen or monovalent hydrocarbon groups of 1 to 15carbon atoms which may contain a hetero atom, for example, straight,branched or cyclic alkyl groups such as methyl, ethyl, propyl,isopropyl, n-butyl, sec-butyl, tert-butyl, tert-amyl, n-pentyl, n-hexyl,n-octyl, n-nonyl, n-decyl, cyclopentyl, cyclohexyl, cyclopentylmethyl,cyclopentylethyl, cyclopentylbutyl, cyclohexylmethyl, cyclohexylethyl,and cyclohexylbutyl, and substituted ones of these groups in which somehydrogen atoms are substituted with hydroxyl, alkoxy, carboxy,alkoxycarbonyl, oxo, amino, alkylamino, cyano, mercapto, alkylthio, andsulfo groups. R¹⁶ to R²⁵, for example, a pair of R¹⁶ and R¹⁷, a pair ofR¹⁶ and R¹⁸, a pair of R¹⁷ and R¹⁹, a pair of R¹⁸ and R¹⁹, a pair of R²⁰and R²¹, or a pair of R²² and R²³, taken together, may form a ring. WhenR¹⁶ to R²⁶ form a ring, they are divalent hydrocarbon groups of 1 to 15carbon atoms which may contain a hetero atom, examples of which are theabove-exemplified monovalent hydrocarbon groups with one hydrogen atomeliminated. Also, two of R¹⁶ to R²⁵ which are attached to adjacentcarbon atoms (for example, a pair of R¹⁶ and R¹⁸, a pair of R¹⁸ and R²⁴or a pair of R²² and R²⁴) may directly bond together to form a doublebond.

Of the acid labile groups of formula (4), illustrative examples of thestraight or branched groups are given below.

Of the acid labile groups of formula (4), illustrative examples of thecyclic groups include tetrahydrofuran-2-yl,2-methyltetrahydrofuran-2-yl, tetrahydropyran-2-yl and2-methyltetrahydropyran-2-yl.

Illustrative examples of the acid labile groups of formula (5) includetert-butoxycarbonyl, tert-butoxycarbonylmethyl, tert-amyloxycarbonyl,tert-amyloxycarbonylmethyl, 1,1-diethylpropyloxycarbonyl,1,1-diethylpropyloxycarbonylmethyl, 1-ethylcyclopentyloxycarbonyl,1-ethylcyclopentyloxycarbonylmethyl, 1-ethyl-2-cyclopentenyloxycarbonyl,1-ethyl-2-cyclopentenyloxycarbonylmethyl, 1-ethoxyethoxycarbonylmethyl,2-tetrahydropyranyloxycarbonylmethyl, and2-tetrahydrofuranyloxycarbonylmethyl.

Illustrative examples of the acid labile groups of formula (6) include1-methylcyclopentyl, 1-ethylcyclopentyl, 1-n-propylcyclopentyl,1-isopropylcyclopentyl, 1-n-butylcyclopentyl, 1-sec-butylcyclopentyl,1-methylcyclohexyl, 1-ethylcyclohexyl, 3-methyl-1-cyclopenten-3-yl,3-ethyl-1-cyclopenten-3-yl, 3-methyl-1-cyclohexen-3-yl,3-ethyl-1-cyclohexen-3-yl, and 1-cyclohexyl-cyclopentyl.

Illustrative examples of the acid labile groups of formula (7) are givenbelow.

Exemplary of the tertiary alkyl group of 4 to 20 carbon atoms,preferably 4 to 15 carbon atoms, are tert-butyl, tert-amyl,1,1-diethylpropyl, 1-ethylcyclopentyl, 1-butylcyclopentyl,1-ethylcyclohexyl, 1-butylcyclohexyl, 1-ethyl-2-cyclopentenyl,1-ethyl-2-cyclohexenyl, 2-methyl-2-adamantyl, 2-ethyl-2-adamantyl,1-adamantyl-1-methylethyl, 3-ethyl-3-pentyl and dimethylbenzyl.

Exemplary of the trialkylsilyl groups whose alkyl groups each have 1 to6 carbon atoms are trimethylsilyl, triethylsilyl, andtert-butyldimethylsilyl.

Exemplary of the oxoalkyl groups of 4 to 20 carbon atoms are3-oxocyclohexyl and groups represented by the following formulae.

Exemplary of the aryl-substituted alkyl groups of 7 to 20 carbon atomsare benzyl, methylbenzyl, dimethylbenzyl, diphenylmethyl, and1,1-diphenylethyl.

In the resist composition comprising the sulfonyldiazomethane as aphotoacid generator, the resin (A) which changes its solubility in analkaline developer under the action of an acid may be the polymer offormula (2) or (2′), (2″) or (2″′) in which some of the hydrogen atomsof the phenolic hydroxyl groups are crosslinked within a molecule and/orbetween molecules, in a proportion of more than 0 mol % to 50 mol %, onthe average, of the entire phenolic hydroxyl groups on the polymer, withcrosslinking groups having C—O—C linkages represented by the followinggeneral formula (3). With respect to illustrative examples and synthesisof polymers crosslinked with acid labile groups, reference should bemade to JP-A 11-190904.

Herein, each of R⁷ and R⁸ is hydrogen or a straight, branched or cyclicalkyl group of 1 to 8 carbon atoms, or R⁷ and R⁸, taken together, mayform a ring, and each of R⁷ and R⁸ is a straight or branched alkylenegroup of 1 to 8 carbon atoms when they form a ring. R⁹ is a straight,branched or cyclic alkylene group of 1 to 10 carbon atoms. Letter “b” is0 or an integer of 1 to 10. AA is an a-valent aliphatic or alicyclicsaturated hydrocarbon group, aromatic hydrocarbon group or heterocyclicgroup of 1 to 50 carbon atoms, which may be separated by a hetero atomand in which some of the hydrogen atom attached to carbon atoms may besubstituted with hydroxyl, carboxyl, carbonyl or halogen. Letter “a” isan integer of 1 to 7.

Preferably in formula (3), R⁷ is methyl, R⁸ is hydrogen, “a” is 1, “b”is 0, and AA is ethylene, 1,4-butylene or 1,4-cyclohexylene.

It is noted that these polymers which are crosslinked within themolecule or between molecules with crosslinking groups having C—O—Clinkages can be synthesized by reacting a corresponding non-crosslinkedpolymer with an alkenyl ether in the presence of an acid catalyst in aconventional manner.

If decomposition of other acid labile groups proceeds under acidcatalyst conditions, the end product can be obtained by once reactingthe alkenyl ether with hydrochloric acid or the like for conversion to ahalogenated alkyl ether and reacting it with the polymer under basicconditions in a conventional manner.

Illustrative, non-limiting, examples of the alkenyl ether includeethylene glycol divinyl ether, triethylene glycol divinyl ether,1,2-propanediol divinyl ether, 1,3-propanediol divinyl ether,1,3-butanediol divinyl ether, 1,4-butanediol divinyl ether, neopentylglycol divinyl ether, trimethylolpropane trivinyl ether,trimethylolethane trivinyl ether, hexanediol divinyl ether, and1,4-cyclohexanediol divinyl ether.

In the chemical amplification type positive resist composition, theresin used as component (A) is as described above while the preferredacid labile groups to be substituted for phenolic hydroxyl groups are1-ethoxyethyl, 1-ethoxypropyl, tetrahydrofuranyl, tetrahydropyranyl,tert-butyl, tert-amyl, 1-ethylcyclohexyloxycarbonylmethyl,tert-butoxycarbonyl, tert-butoxycarbonylmethyl, and substituents offormula (3) wherein R⁷ is methyl, R⁸ is hydrogen, “a” is 1, “b” is 0,and AA is ethylene, 1,4-butylene or 1,4-cyclohexylene. Also preferably,the hydrogen atoms of carboxyl groups of methacrylic acid or acrylicacid are protected with substituent groups as typified by tert-butyl,tert-amyl, 2-methyl-2-adamantyl, 2-ethyl-2-adamantyl,1-ethylcyclopentyl, 1-ethylcyclohexyl, 1-cyclohexylcyclopentyl,1-ethylnorbornyl, tetrahydrofuranyl and tetrahydropyranyl.

In a single polymer, these substituents may be incorporated alone or inadmixture of two or more types. A blend of two or more polymers havingsubstituents of different types is also acceptable.

The percent proportion of these substituents substituting for phenol andcarboxyl groups in the polymer is not critical. Preferably the percentsubstitution is selected such that when a resist composition comprisingthe polymer is applied onto a substrate to form a coating, the unexposedarea of the coating may have a dissolution rate of 0.01 to 10 Å/sec in a2.38% tetramethylammonium hydroxide (TMAH) developer.

On use of a polymer containing a greater proportion of carboxyl groupswhich can reduce the alkali dissolution rate, the percent substitutionmust be increased or non-acid-decomposable substituents to be describedlater must be introduced.

When acid labile groups for intramolecular and/or intermolecularcrosslinking are to be introduced, the percent proportion ofcrosslinking substituents is preferably up to 20 mol %, more preferablyup to 10 mol %, based on the entire hydrogen atoms of phenolic hydroxylgroups. If the percent substitution of crosslinking substituents is toohigh, crosslinking results in a higher molecular weight which canadversely affect dissolution, stability and resolution. It is alsopreferred to further introduce another non-crosslinking acid labilegroup into the crosslinked polymer at a percent substitution of up to 10mol % for adjusting the dissolution rate to fall within the above range.

In the case of poly(p-hydroxystyrene), the optimum percent substitutiondiffers between a substituent having a strong dissolution inhibitoryaction such as a tert-butoxycarbonyl group and a substituent having aweak dissolution inhibitory action such as an acetal group although theoverall percent substitution is preferably 10 to 40 mol %, morepreferably 20 to 30 mol %, based on the entire hydrogen atoms ofphenolic hydroxyl groups in the polymer.

Polymers having such acid labile groups introduced therein shouldpreferably have a weight average molecular weight (Mw) of 3,000 to100,000. With a Mw of less than 3,000, polymers would perform poorly andoften lack heat resistance and film formability. Polymers with a Mw ofmore than 100,000 would be less soluble in a developer and a resistsolvent.

Where non-crosslinking acid labile groups are introduced, the polymershould preferably have a dispersity (Mw/Mn) of up to 3.5, preferably upto 1.5. A polymer with a dispersity of more than 3.5 often results in alow resolution. Where crosslinking acid labile groups are introduced,the starting alkali-soluble resin should preferably have a dispersity(Mw/Mn) of up to 1.5, and the dispersity is kept at 3 or lower evenafter protection with crosslinking acid labile groups. If the dispersityis higher than 3, dissolution, coating, storage stability and/orresolution is often poor.

To impart a certain function, suitable substituent groups may beintroduced into some of the phenolic hydroxyl and carboxyl groups on theacid labile group-protected polymer. Exemplary are substituent groupsfor improving adhesion to the substrate, non-acid-labile groups foradjusting dissolution in an alkali developer, and substituent groups forimproving etching resistance. Illustrative, non-limiting, substituentgroups include 2-hydroxyethyl, 2-hydroxypropyl, methoxymethyl,methoxycarbonyl, ethoxycarbonyl, methoxycarbonylmethyl,ethoxycarbonylmethyl, 4-methyl-2-oxo-4-oxolanyl,4-methyl-2-oxo-4-oxanyl, methyl, ethyl, propyl, n-butyl, sec-butyl,acetyl, pivaloyl, adamantyl, isobornyl, and cyclohexyl.

In the resist composition of the invention, the above-described resin isadded in any desired amount, and usually 65 to 99 parts by weight,preferably 70 to 98 parts by weight per 100 parts by weight of thesolids in the composition. The term “solids” is used to encompass allcomponents in the resist composition excluding the solvent.

Illustrative examples of the sulfonyldiazomethane compounds of formulae(1) and (1a) as the photoacid generator (B) are as described above.Listing again, examples of bilaterally symmetric bissulfonyldiazomethaneinclude, but are not limited to,

-   bis(2-(n-butyloxy)-5-methylbenzenesulfonyl)diazomethane,-   bis(2-(n-pentyloxy)-5-methylbenzenesulfonyl)diazomethane,-   bis(2-(n-hexyloxy)-5-methylbenzenesulfonyl)diazomethane,-   bis(2-(n-heptyloxy)-5-methylbenzenesulfonyl)diazomethane,-   bis(2-(n-octyloxy)-5-methylbenzenesulfonyl)diazomethane,-   bis(2-(n-nonyloxy)-5-methylbenzenesulfonyl)diazomethane,-   bis(2-(n-butyloxy)-5-ethylbenzenesulfonyl)diazomethane,-   bis(2-(n-pentyloxy)-5-ethylbenzenesulfonyl)diazomethane,-   bis(2-(n-hexyloxy)-5-ethylbenzenesulfonyl)diazomethane,-   bis(2-(n-heptyloxy)-5-ethylbenzenesulfonyl)diazomethane,-   bis(2-(n-octyloxy)-5-ethylbenzenesulfonyl)diazomethane,-   bis(2-(n-nonyloxy)-5-ethylbenzenesulfonyl)diazomethane,-   bis(2-(n-butyloxy)-5-isopropylbenzenesulfonyl)diazomethane,-   bis(2-(n-pentyloxy)-5-isopropylbenzenesulfonyl)diazomethane,-   bis(2-(n-hexyloxy)-5-isopropylbenzenesulfonyl)diazomethane,-   bis(2-(n-heptyloxy)-5-isopropylbenzenesulfonyl)diazomethane,-   bis(2-(n-octyloxy)-5-isopropylbenzenesulfonyl)diazomethane,-   bis(2-(n-nonyloxy)-5-isopropylbenzenesulfonyl)diazomethane,-   bis(2-(n-butyloxy)-5-tert-butylbenzenesulfonyl)diazomethane,-   bis(2-(n-pentyloxy)-5-tert-butylbenzenesulfonyl)diazomethane,-   bis(2-(n-hexyloxy)-5-tert-butylbenzenesulfonyl)diazomethane,-   bis(2-(n-heptyloxy)-5-tert-butylbenzenesulfonyl)diazomethane,-   bis(2-(n-octyloxy)-5-tert-butylbenzenesulfonyl)diazomethane,-   bis(2-(n-nonyloxy)-5-tert-butylbenzenesulfonyl)diazomethane, etc. Of    these, preferred are-   bis(2-(n-butyloxy)-5-tert-butylbenzenesulfonyl)diazomethane,-   bis(2-(n-pentyloxy)-5-tert-butylbenzenesulfonyl)diazomethane,-   and bis(2-(n-hexyloxy)-5-tert-butylbenzenesulfonyl)diazomethane.

Examples of bilaterally asymmetric sulfonyldiazomethane include, but arenot limited to,

-   (2-(n-butyloxy)-5-methylbenzenesulfonyl)(tert-butylsulfonyl)diazomethane,-   (2-(n-pentyloxy)-5-methylbenzenesulfonyl)(tert-butylsulfonyl)diazomethane,-   (2-(n-hexyloxy)-5-methylbenzenesulfonyl)(tert-butylsulfonyl)diazomethane,-   (2-(n-butyloxy)-5-tert-butylbenzenesulfonyl)(tert-butylsulfonyl)diazomethane,-   (2-(n-pentyloxy)-5-tert-butylbenzenesulfonyl)(tert-butylsulfonyl)diazomethane,-   (2-(n-hexyloxy)-5-tert-butylbenzenesulfonyl)(tert-butylsulfonyl)diazomethane,-   (2-(n-butyloxy)-5-methylbenzenesulfonyl)(cyclohexylsulfonyl)diazomethane,-   (2-(n-pentyloxy)-5-methylbenzenesulfonyl)(cyclohexylsulfonyl)diazomethane,-   (2-(n-hexyloxy)-5-methylbenzenesulfonyl)(cyclohexylsulfonyl)diazomethane,-   (2-(n-butyloxy)-5-tert-butylbenzenesulfonyl)(cyclohexylsulfonyl)diazomethane,-   (2-(n-pentyloxy)-5-tert-butylbenzenesulfonyl)(cyclohexylsulfonyl)diazomethane,-   (2-(n-hexyloxy)-5-tert-butylbenzenesulfonyl)(cyclohexylsulfonyl)diazomethane,-   (2-(n-butyloxy)-5-methylbenzenesulfonyl)(2,4-dimethylbenzenesulfonyl)diazomethane,-   (2-(n-pentyloxy)-5-methylbenzenesulfonyl)(2,4-dimethylbenzenesulfonyl)diazomethane,-   (2-(n-hexyloxy)-5-methylbenzenesulfonyl)(2,4-dimethylbenzenesulfonyl)diazomethane,-   (2-(n-butyloxy)-5-tert-butylbenzenesulfonyl)(2,4-dimethylbenzenesulfonyl)diazomethane,-   (2-(n-pentyloxy)-5-tert-butylbenzenesulfonyl)(2,4-dimethylbenzenesulfonyl)diazomethane,-   (2-(n-hexyloxy)-5-tert-butylbenzenesulfonyl)(2,4-dimethylbenzenesulfonyl)diazomethane,-   (2-(n-butyloxy)-5-methylbenzenesulfonyl)(2-naphthalenesulfonyl)diazomethane,-   (2-(n-pentyloxy)-5-methylbenzenesulfonyl)(2-naphthalenesulfonyl)diazomethane,-   (2-(n-hexyloxy)-5-methylbenzenesulfonyl)(2-naphthalenesulfonyl)diazomethane,-   (2-(n-butyloxy)-5-tert-butylbenzenesulfonyl)(2-naphthalenesulfonyl)diazomethane,-   (2-(n-pentyloxy)-5-tert-butylbenzenesulfonyl)(2-naphthalenesulfonyl)diazomethane,-   (2-(n-hexyloxy)-5-tert-butylbenzenesulfonyl)(2-naphthalenesulfonyl)diazomethane,    etc.

Examples of the sulfonyl-carbonyldiazomethane include, but are notlimited to,

-   (2-(n-butyloxy)-5-methylbenzenesulfonyl)(tert-butylcarbonyl)diazomethane,-   (2-(n-pentyloxy)-5-methylbenzenesulfonyl)(tert-butylcarbonyl)diazomethane,-   (2-(n-hexyloxy)-5-methylbenzenesulfonyl)(tert-butylcarbonyl)diazomethane,-   (2-(n-butyloxy)-5-tert-butylbenzenesulfonyl)(tert-butylcarbonyl)diazomethane,-   (2-(n-pentyloxy)-5-tert-butylbenzenesulfonyl)(tert-butylcarbonyl)diazomethane,-   (2-(n-hexyloxy)-5-tert-butylbenzenesulfonyl)(tert-butylcarbonyl)diazomethane,-   (2-(n-butyloxy)-5-methylbenzenesulfonyl)(benzenecarbonyl)diazomethane,-   (2-(n-pentyloxy)-5-methylbenzenesulfonyl)(benzenecarbonyl)diazomethane,-   (2-(n-hexyloxy)-5-methylbenzenesulfonyl)(benzenecarbonyl)diazomethane,-   (2-(n-butyloxy)-5-tert-butylbenzenesulfonyl)(benzenecarbonyl)diazomethane,-   (2-(n-pentyloxy)-5-tert-butylbenzenesulfonyl)(benzenecarbonyl)diazomethane,-   (2-(n-hexyloxy)-5-tert-butylbenzenesulfonyl)(benzenecarbonyl)diazomethane,-   (2-(n-butyloxy)-5-methylbenzenesulfonyl)(2-naphthalenecarbonyl)diazomethane,-   (2-(n-pentyloxy)-5-methylbenzenesulfonyl)(2-naphthalenecarbonyl)diazomethane,-   (2-(n-hexyloxy)-5-methylbenzenesulfonyl)(2-naphthalenecarbonyl)diazomethane,-   (2-(n-butyloxy)-5-tert-butylbenzenesulfonyl)(2-naphthalenecarbonyl)diazomethane,-   (2-(n-pentyloxy)-5-tert-butylbenzenesulfonyl)(2-naphthalenecarbonyl)diazomethane,-   (2-(n-hexyloxy)-5-tert-butylbenzenesulfonyl)(2-naphthalenecarbonyl)diazomethane,    etc.

In the chemical amplification resist composition, an appropriate amountof the sulfonyldiazomethane compound of formula (1) or (1a) added isfrom more than 0 part to 10 parts by weight, and preferably from 1 to 5parts by weight, per 100 parts by weight of the solids in thecomposition. The sulfonyldiazomethane compound is used at least in anamount to generate a sufficient amount of acid to deblock acid labilegroups in the polymer. Too large amounts may excessively reduce thetransmittance of resist film, failing to form a rectangular pattern, andgive rise to problems of abnormal particles and deposits during resiststorage. The photoacid generators may be used alone or in admixture oftwo or more.

Component (C)

In one preferred embodiment, the resist composition further contains (C)a compound capable of generating an acid upon exposure to high energyradiation, that is, a second photoacid generator other than thesulfonyldiazomethane (B) having formula (1) or (1a). Suitable secondphotoacid generators include sulfonium salts, iodonium salts,sulfonyldiazomethane and N-sulfonyloxyimide photoacid generators.Exemplary second photoacid generators are given below while they may beused alone or in admixture of two or more.

Sulfonium salts are salts of sulfonium cations with sulfonates.Exemplary sulfonium cations include triphenylsulfonium,(4-tert-butoxyphenyl)diphenylsulfonium,bis(4-tert-butoxyphenyl)phenylsulfonium,tris(4-tert-butoxyphenyl)sulfonium,(3-tert-butoxyphenyl)diphenylsulfonium,bis(3-tert-butoxyphenyl)phenylsulfonium,tris(3-tert-butoxyphenyl)sulfonium,(3,4-di-tert-butoxyphenyl)diphenylsulfonium,bis(3,4-di-tert-butoxyphenyl)phenylsulfonium,tris(3,4-di-tert-butoxyphenyl)sulfonium,diphenyl(4-thiophenoxyphenyl)sulfonium,(4-tert-butoxycarbonylmethyloxyphenyl)diphenylsulfonium,tris(4-tert-butoxycarbonylmethyloxyphenyl)sulfonium,(4-tert-butoxyphenyl)bis(4-dimethylaminophenyl)sulfonium,tris(4-dimethylaminophenyl)sulfonium, 2-naphthyldiphenylsulfonium,dimethyl-2-naphthylsulfonium, 4-hydroxyphenyldimethylsulfonium,4-methoxyphenyldimethylsulfonium, trimethylsulfonium,2-oxocyclohexylcyclohexylmethylsulfonium, trinaphthylsulfonium,tribenzylsulfonium, diphenylmethylsulfonium, dimethylphenylsulfonium,and 2-oxo-2-phenylethylthiacyclopentanium. Exemplary sulfonates includetrifluoromethanesulfonate, nonafluorobutanesulfonate,heptadecafluorooctanesulfonate, 2,2,2-trifluoroethanesulfonate,pentafluorobenzenesulfonate, 4-trifluoromethylbenzenesulfonate,4-fluorobenzenesulfonate, mesitylenesulfonate,2,4,6-triisopropylbenzenesulfonate, toluenesulfonate, benzenesulfonate,4-(4′-toluenesulfonyloxy)benzenesulfonate, naphthalenesulfonate,camphorsulfonate, octanesulfonate, dodecylbenzenesulfonate,butanesulfonate, and methanesulfonate. Sulfonium salts based oncombination of the foregoing examples are included.

Iodinium salts are salts of iodonium cations with sulfonates. Exemplaryiodinium cations are aryliodonium cations including diphenyliodinium,bis(4-tert-butylphenyl)iodonium, 4-tert-butoxyphenylphenyliodonium, and4-methoxyphenylphenyliodonium. Exemplary sulfonates includetrifluoromethanesulfonate, nonafluorobutanesulfonate,heptadecafluorooctanesulfonate, 2,2,2-trifluoroethanesulfonate,pentafluorobenzenesulfonate, 4-trifluoromethylbenzenesulfonate,4-fluorobenzenesulfonate, mesitylenesulfonate,2,4,6-triisopropylbenzenesulfonate, toluenesulfonate, benzenesulfonate,4-(4-toluenesulfonyloxy)benzenesulfonate, naphthalenesulfonate,camphorsulfonate, octanesulfonate, dodecylbenzenesulfonate,butanesulfonate, and methanesulfonate. Iodonium salts based oncombination of the foregoing examples are included.

Exemplary sulfonyldiazomethane compounds include bissulfonyldiazomethanecompounds and sulfonyl-carbonyldiazomethane compounds such as

-   bis(ethylsulfonyl)diazomethane,-   bis(1-methylpropylsulfonyl)diazomethane,-   bis(2-methylpropylsulfonyl)diazomethane,-   bis(1,1-dimethylethylsulfonyl)diazomethane,-   bis(cyclohexylsulfonyl)diazomethane,-   bis(perfluoroisopropylsulfonyl)diazomethane,-   bis(phenylsulfonyl)diazomethane,-   bis(4-methylphenylsulfonyl)diazomethane,-   bis(2,4-dimethylphenylsulfonyl)diazomethane,-   bis(2-naphthylsulfonyl)diazomethane,-   bis(4-acetyloxyphenylsulfonyl)diazomethane,-   bis(4-methanesulfonyloxyphenylsulfonyl)diazomethane,-   bis(4-(4-toluenesulfonyloxy)phenylsulfonyl)diazomethane,    4-methylphenylsulfonylbenzoyldiazomethane,    tert-butylcarbonyl-4-methylphenylsulfonyldiazomethane,    2-naphthylsulfonylbenzoyldiazomethane,    4-methylphenylsulfonyl-2-naphthoyldiazomethane,    methylsulfonylbenzoyldiazomethane, and    tert-butoxycarbonyl-4-methylphenylsulfonyldiazomethane.

N-sulfonyloxyimide photoacid generators include combinations of imideskeletons with sulfonates. Exemplary imide skeletons are succinimide,naphthalene dicarboxylic acid imide, phthalimide, cyclohexyldicarboxylicacid imide, 5-norbornene-2,3-dicarboxylic acid imide, and7-oxabicyclo[2.2.1]-5-heptene-2,3-dicarboxylic acid imide. Exemplarysulfonates include trifluoromethanesulfonate, nonafluorobutanesulfonate,heptadecafluorooctanesulfonate, 2,2,2-trifluoroethanesulfonate,pentafluorobenzenesulfonate, 4-trifluoromethylbenzenesulfonate,4-fluorobenzenesulfonate, mesitylenesulfonate,2,4,6-triisopropylbenzenesulfonate, toluenesulfonate, benzenesulfonate,naphthalenesulfonate, camphorsulfonate, octanesulfonate,dodecylbenzenesulfonate, butanesulfonate, and methanesulfonate.

Benzoinsulfonate photoacid generators include benzoin tosylate, benzoinmesylate, and benzoin butanesulfonate.

Pyrogallol trisulfonate photoacid generators include pyrogallol,fluoroglycine, catechol, resorcinol, hydroquinone, in which all thehydroxyl groups are substituted with trifluoromethanesulfonate,nonafluorobutanesulfonate, heptadecafluorooctanesulfonate,2,2,2-trifluoroethanesulfonate, pentafluorobenzenesulfonate,4-trifluoromethylbenzenesulfonate, 4-fluorobenzenesulfonate,toluenesulfonate, benzenesulfonate, naphthalenesulfonate,camphorsulfonate, octanesulfonate, dodecylbenzenesulfonate,butanesulfonate, and methanesulfonate.

Nitrobenzyl sulfonate photoacid generators include 2,4-dinitrobenzylsulfonate, 2-nitrobenzyl sulfonate, and 2,6-dinitrobenzyl sulfonate,with exemplary sulfonates including trifluoromethanesulfonate,nonafluorobutanesulfonate, heptadecafluorooctanesulfonate,2,2,2-trifluoroethanesulfonate, pentafluorobenzenesulfonate,4-trifluoromethylbenzenesulfonate, 4-fluorobenzenesulfonate,toluenesulfonate, benzenesulfonate, naphthalenesulfonate,camphorsulfonate, octanesulfonate, dodecylbenzenesulfonate,butanesulfonate, and methanesulfonate. Also useful are analogousnitrobenzyl sulfonate compounds in which the nitro group on the benzylside is substituted with a trifluoromethyl group.

Sulfone photoacid generators include

-   bis(phenylsulfonyl)methane,-   bis(4-methylphenylsulfonyl)methane,-   bis(2-naphthylsulfonyl)methane,-   2,2-bis(phenylsulfonyl)propane,-   2,2-bis(4-methylphenylsulfonyl)propane,-   2,2-bis(2-naphthylsulfonyl)propane,-   2-methyl-2-(p-toluenesulfonyl)propiophenone,-   2-cyclohexylcarbonyl-2-(p-toluenesulfonyl)propane, and-   2,4-dimethyl-2-(p-toluenesulfonyl)pentan-3-one.

Photoacid generators in the form of glyoxime derivatives are describedin Japanese Patent No. 2,906,999 and JP-A 9-301948 and include

-   bis-O-(p-toluenesulfonyl)-α-dimethylglyoxime,-   bis-O-(p-toluenesulfonyl)-α-diphenylglyoxime,-   bis-O-(p-toluenesulfonyl)-α-dicyclohexylglyoxime,-   bis-O-(p-toluenesulfonyl)-2,3-pentanedioneglyoxime,-   bis-O-(n-butanesulfonyl)-α-dimethylglyoxime,-   bis-O-(n-butanesulfonyl)-α-diphenylglyoxime,-   bis-O-(n-butanesulfonyl)-α-dicyclohexylglyoxime,-   bis-O-(methanesulfonyl)-α-dimethylglyoxime,-   bis-O-(trifluoromethanesulfonyl)-α-dimethylglyoxime,-   bis-O-(2,2,2-trifluoroethanesulfonyl)-α-dimethylglyoxime,-   bis-O-(10-camphorsulfonyl)-α-dimethylglyoxime,-   bis-O-(benzenesulfonyl)-α-dimethylglyoxime,-   bis-O-(p-fluorobenzenesulfonyl)-α-dimethylglyoxime,-   bis-O-(p-trifluoromethylbenzenesulfonyl)-α-dimethylglyoxime,-   bis-O-(xylenesulfonyl)-α-dimethylglyoxime,-   bis-O-(trifluoromethanesulfonyl)-nioxime,-   bis-O-(2,2,2-trifluoroethanesulfonyl)-nioxime,-   bis-O-(10-camphorsulfonyl)-nioxime,-   bis-O-(benzenesulfonyl)-nioxime,-   bis-O-(p-fluorobenzenesulfonyl)-nioxime,-   bis-O-(p-trifluoromethylbenzenesulfonyl)-nioxime, and-   bis-O-(xylenesulfonyl)-nioxime.

Also included are the oxime sulfonates described in U.S. Pat. No.6,004,724, for example,

-   (5-(4-toluenesulfonyl)oxyimino-5H-thiophen-2-ylidene)phenylacetonitrile,-   (5-(10-camphorsulfonyl)oxyimino-5H-thiophen-2-ylidene)phenylacetonitrile,-   (5-n-octanesulfonyloxyimino-5H-thiophen-2-ylidene)phenylacetonitrile,-   (5-(4-toluenesulfonyl)oxyimino-5H-thiophen-2-ylidene)(2-methylphenyl)acetonitrile,-   (5-(10-camphorsulfonyl)oxyimino-5H-thiophen-2-ylidene)(2-methylphenyl)acetonitrile,-   (5-n-octanesulfonyloxyimino-5H-thiophen-2-ylidene)(2-methylphenyl)acetonitrile,    etc.

Also included are the oxime sulfonates described in U.S. Pat. No.6,261,738 and JP-A 2000-314956, for example,

-   2,2,2-trifluoro-1-phenyl-ethanone oxime-O-methylsulfonate;-   2,2,2-trifluoro-1-phenyl-ethanone oxime-O-(10-camphorylsulfonate);-   2,2,2-trifluoro-1-phenyl-ethanone    oxime-O-(4-methoxyphenylsulfonate);-   2,2,2-trifluoro-1-phenyl-ethanone oxime-O-(1-naphthylsulfonate);-   2,2,2-trifluoro-1-phenyl-ethanone oxime-O-(2-naphthylsulfonate);-   2,2,2-trifluoro-1-phenyl-ethanone    oxime-O-(2,4,6-trimethylphenylsulfonate);-   2,2,2-trifluoro-1-(4-methylphenyl)-ethanone    oxime-O-(10-camphorylsulfonate);-   2,2,2-trifluoro-1-(4-methylphenyl)-ethanone    oxime-O-(methylsulfonate);-   2,2,2-trifluoro-1-(2-methylphenyl)-ethanone    oxime-O-(10-camphorylsulfonate);-   2,2,2-trifluoro-1-(2,4-dimethylphenyl)-ethanone    oxime-O-(10-camphorylsulfonate);-   2,2,2-trifluoro-1-(2,4-dimethylphenyl)-ethanone    oxime-O-(1-naphthylsulfonate);-   2,2,2-trifluoro-1-(2,4-dimethylphenyl)-ethanone    oxime-O-(2-naphthylsulfonate);-   2,2,2-trifluoro-1-(2,4,6-trimethylphenyl)-ethanone    oxime-O-(10-camphorylsulfonate);-   2,2,2-trifluoro-1-(2,4,6-trimethylphenyl)-ethanone    oxime-O-(1-naphthylsulfonate);-   2,2,2-trifluoro-1-(2,4,6-trimethylphenyl)-ethanone    oxime-O-(2-naphthylsulfonate);-   2,2,2-trifluoro-1-(4-methoxyphenyl)-ethanone    oxime-O-methylsulfonate;-   2,2,2-trifluoro-1-(4-methylthiophenyl)-ethanone    oxime-O-methylsulfonate;-   2,2,2-trifluoro-1-(3,4-dimethoxyphenyl)-ethanone    oxime-O-methylsulfonate;-   2,2,3,3,4,4,4-heptafluoro-1-phenyl-butanone    oxime-O-(10-camphorylsulfonate);-   2,2,2-trifluoro-1-(phenyl)-ethanone oxime-O-methylsulfonate;-   2,2,2-trifluoro-1-(phenyl)-ethanone oxime-O-10-camphorylsulfonate;-   2,2,2-trifluoro-1-(phenyl)-ethanone    oxime-O-(4-methoxyphenyl)sulfonate;-   2,2,2-trifluoro-1-(phenyl)-ethanone oxime-O-(1-naphthyl)sulfonate;-   2,2,2-trifluoro-1-(phenyl)-ethanone oxime-O-(2-naphthyl)sulfonate;-   2,2,2-trifluoro-1-(phenyl)-ethanone    oxime-O-(2,4,6-trimethylphenyl)sulfonate;-   2,2,2-trifluoro-1-(4-methylphenyl)-ethanone    oxime-O-(10-camphoryl)sulfonate;-   2,2,2-trifluoro-1-(4-methylphenyl)-ethanone oxime-O-methylsulfonate;-   2,2,2-trifluoro-1-(2-methylphenyl)-ethanone    oxime-O-(10-camphoryl)sulfonate;-   2,2,2-trifluoro-1-(2,4-dimethylphenyl)-ethanone    oxime-O-(1-naphthyl)sulfonate;-   2,2,2-trifluoro-1-(2,4-dimethylphenyl)-ethanone    oxime-O-(2-naphthyl)sulfonate;-   2,2,2-trifluoro-1-(2,4,6-trimethylphenyl)-ethanone    oxime-O-(10-camphoryl)sulfonate;-   2,2,2-trifluoro-1-(2,4,6-trimethylphenyl)-ethanone    oxime-O-(1-naphthyl)sulfonate;-   2,2,2-trifluoro-1-(2,4,6-trimethylphenyl)-ethanone    oxime-O-(2-naphthyl)sulfonate;-   2,2,2-trifluoro-1-(4-methoxyphenyl)-ethanone    oxime-O-methylsulfonate;-   2,2,2-trifluoro-1-(4-thiomethylphenyl)-ethanone    oxime-O-methylsulfonate;-   2,2,2-trifluoro-1-(3,4-dimethoxyphenyl)-ethanone    oxime-O-methylsulfonate;-   2,2,2-trifluoro-1-(4-methoxyphenyl)-ethanone    oxime-O-(4-methylphenyl)sulfonate;-   2,2,2-trifluoro-1-(4-methoxyphenyl)-ethanone    oxime-O-(4-methoxyphenyl)sulfonate;-   2,2,2-trifluoro-1-(4-methoxyphenyl)-ethanone    oxime-O-(4-dodecylphenyl)sulfonate;-   2,2,2-trifluoro-1-(4-methoxyphenyl)-ethanone oxime-O-octylsulfonate;-   2,2,2-trifluoro-1-(4-thiomethylphenyl)-ethanone    oxime-O-(4-methoxyphenyl)sulfonate;-   2,2,2-trifluoro-1-(4-thiomethylphenyl)-ethanone    oxime-O-(4-dodecylphenyl)sulfonate;-   2,2,2-trifluoro-1-(4-thiomethylphenyl)-ethanone    oxime-O-octylsulfonate;-   2,2,2-trifluoro-1-(4-thiomethylphenyl)-ethanone    oxime-O-(2-naphthyl)sulfonate;-   2,2,2-trifluoro-1-(2-methylphenyl)-ethanone oxime-O-methylsulfonate;-   2,2,2-trifluoro-1-(4-methylphenyl)-ethanone oxime-O-phenylsulfonate;-   2,2,2-trifluoro-1-(4-chlorophenyl)-ethanone oxime-O-phenylsulfonate;-   2,2,3,3,4,4,4-heptafluoro-1-(phenyl)-butanone    oxime-O-(10-camphoryl)sulfonate;-   2,2,2-trifluoro-1-naphthyl-ethanone oxime-O-methylsulfonate;-   2,2,2-trifluoro-2-naphthyl-ethanone oxime-O-methylsulfonate;-   2,2,2-trifluoro-1-[4-benzylphenyl]-ethanone oxime-O-methylsulfonate;-   2,2,2-trifluoro-1-[4-(phenyl-1,4-dioxa-but-1-yl)phenyl]-ethanone    oxime-O-methylsulfonate;-   2,2,2-trifluoro-1-naphthyl-ethanone oxime-O-propylsulfonate;-   2,2,2-trifluoro-2-naphthyl-ethanone oxime-O-propylsulfonate;-   2,2,2-trifluoro-1-[4-benzylphenyl]-ethanone oxime-O-propylsulfonate;-   2,2,2-trifluoro-1-[4-methylsulfonylphenyl]-ethanone    oxime-O-propylsulfonate;-   1,3-bis[1-(4-phenoxyphenyl)-2,2,2-trifluoroethanone    oxime-O-sulfonyl]phenyl;-   2,2,2-trifluoro-1-[4-methylsulfonyloxyphenyl]-ethanone    oxime-O-propylsulfonate;-   2,2,2-trifluoro-1-[4-methylcarbonyloxyphenyl]-ethanone    oxime-O-propylsulfonate;-   2,2,2-trifluoro-1-[6H,7H-5,8-dioxonaphth-2-yl]-ethanone    oxime-O-propylsulfonate;-   2,2,2-trifluoro-1-[4-methoxycarbonylmethoxyphenyl]-ethanone    oxime-O-propylsulfonate;-   2,2,2-trifluoro-1-[4-(methoxycarbonyl)-(4-amino-1-oxa-pent-1-yl)-phenyl]-ethanone    oxime-O-propylsulfonate;-   2,2,2-trifluoro-1-[3,5-dimethyl-4-ethoxyphenyl]-ethanone    oxime-O-propylsulfonate;-   2,2,2-trifluoro-1-[4-benzyloxyphenyl]-ethanone    oxime-O-propylsulfonate;-   2,2,2-trifluoro-1-[2-thiophenyl]-ethanone oxime-O-propylsulfonate;    and-   2,2,2-trifluoro-1-[1-dioxa-thiophen-2-yl)]-ethanone    oxime-O-propylsulfonate.

Also included are the oxime sulfonates described in JP-A 9-95479 andJP-A 9-230588 and the references cited therein, for example,

-   α-(p-toluenesulfonyloxyimino)-phenylacetonitrile,-   α-(p-chlorobenzenesulfonyloxyimino)-phenylacetonitrile,-   α-(4-nitrobenzenesulfonyloxyimino)-phenylacetonitrile,-   α-(4-nitro-2-trifluoromethylbenzenesulfonyloxyimino)phenylacetonitrile,-   α-(benzenesulfonyloxyimino)-4-chlorophenylacetonitrile,-   α-(benzenesulfonyloxyimino)-2,4-dichlorophenylacetonitrile,-   α-(benzenesulfonyloxyimino)-2,6-dichlorophenylacetonitrile,-   α-(benzenesulfonyloxyimino)-4-methoxyphenylacetonitrile,-   α-(2-chlorobenzenesulfonyloxyimino)-4-methoxyphenylacetonitrile,-   α-(benzenesulfonyloxyimino)-2-thienylacetonitrile,-   α-(4-dodecylbenzenesulfonyloxyimino)-phenylacetonitrile,-   α-[(4-toluenesulfonyloxyimino)-4-methoxyphenyl]acetonitrile,-   α-[(dodecylbenzenesulfonyloxyimino)-4-methoxyphenyl]acetonitrile,-   α-(tosyloxyimino)-3-thienylacetonitrile,-   α-(methylsulfonyloxyimino)-1-cyclopentenylacetonitrile,-   α-(ethylsulfonyloxyimino)-1-cyclopentenylacetonitrile,-   α-(isopropylsulfonyloxyimino)-1-cyclopentenylacetonitrile,-   α-(n-butylsulfonyloxyimino)-1-cyclopentenylacetonitrile,-   α-(ethylsulfonyloxyimino)-1-cyclohexenylacetonitrile,-   α-(isopropylsulfonyloxyimino)-1-cyclohexenylacetonitrile, and-   α-(n-butylsulfonyloxyimino)-1-cyclohexenylacetonitrile.

Suitable bisoxime sulfonates include those described in JP-A 9-208554,for example,

-   bis(α-(4-toluenesulfonyloxy)imino)-p-phenylenediacetonitrile,-   bis(α-(benzenesulfonyloxy)imino)-p-phenylenediacetonitrile,-   bis(α-(methanesulfonyloxy)imino)-p-phenylenediacetonitrile,-   bis(α-(butanesulfonyloxy)imino)-p-phenylenediacetonitrile,-   bis(α-(10-camphorsulfonyloxy)imino)-p-phenylenediacetonitrile,-   bis(α-(4-toluenesulfonyloxy)imino)-p-phenylenediacetonitrile,-   bis(α-(trifluoromethanesulfonyloxy)imino)-p-phenylenediacetonitrile,-   bis(α-(4-methoxybenzenesulfonyloxy)imino)-p-phenylenediacetonitrile,-   bis(α-(4-toluenesulfonyloxy)imino)-m-phenylenediacetonitrile,-   bis(α-(benzenesulfonyloxy)imino)-m-phenylenediacetonitrile,-   bis(α-(methanesulfonyloxy)imino)-m-phenylenediacetonitrile,-   bis(α-(butanesulfonyloxy)imino)-m-phenylenediacetonitrile,-   bis(α-(10-camphorsulfonyloxy)imino)-m-phenylenediacetonitrile,-   bis(α-(4-toluenesulfonyloxy)imino)-m-phenylenediacetonitrile,-   bis(α-(trifluoromethanesulfonyloxy)imino)-m-phenylenediacetonitrile,-   bis(α-(4-methoxybenzenesulfonyloxy)imino)-m-phenylenediacetonitrile,    etc.

Of these, preferred photoacid generators are sulfonium salts,bissulfonyldiazomethanes, N-sulfonyloxyimides and glyoxime derivatives.More preferred photoacid generators are sulfonium salts,bissulfonyldiazomethanes, and N-sulfonyloxyimides. Typical examplesinclude triphenylsulfonium p-toluenesulfonate, triphenylsulfoniumcamphorsulfonate, triphenylsulfonium pentafluorobenzenesulfonate,triphenylsulfonium nonafluorobutanesulfonate, triphenylsulfonium4-(4′-toluenesulfonyloxy)benzenesulfonate, triphenylsulfonium2,4,6-triisopropylbenzenesulfonate, 4-tert-butoxyphenyldiphenylsulfoniump-toluenesulfonate, 4-tert-butoxyphenyldiphenylsulfoniumcamphorsulfonate, 4-tert-butoxyphenyldiphenylsulfonium4-(4′-toluenesulfonyloxy)benzenesulfonate, tris(4-methylphenyl)sulfoniumcamphorsulfonate, tris(4-tert-butylphenyl)sulfonium camphorsulfonate,bis(tert-butylsulfonyl)diazomethane,bis(cyclohexylsulfonyl)diazomethane,bis(2,4-dimethylphenylsulfonyl)diazomethane,bis(4-tert-butylphenylsulfonyl)diazomethane,N-camphorsulfonyloxy-5-norbornene-2,3-carboxylic acid imide, andN-p-toluenesulfonyloxy-5-norbornene-2,3-carboxylic acid imide.

In the resist composition comprising the sulfonyldiazomethane of formula(1) or (1a) as the first photoacid generator according to the invention,the second photoacid generator (C) may be used in any desired amount aslong as it does not compromise the effects of the sulfonyldiazomethaneof formula (1) or (1a). An appropriate amount of the second photoacidgenerator (C) is 0 to 10 parts, and especially 0 to 5 parts by weightper 100 parts by weight of the solids in the composition. Too high aproportion of the second photoacid generator (C) may give rise toproblems of degraded resolution and foreign matter upon development andresist film peeling. The second photoacid generators may be used aloneor in admixture of two or more. The transmittance of the resist film canbe controlled by using a (second) photoacid generator having a lowtransmittance at the exposure wavelength and adjusting the amount of thephotoacid generator added.

In the resist composition comprising the sulfonyldiazomethane as thephotoacid generator according to the invention, there may be added acompound which is decomposed with an acid to generate an acid, that is,acid-propagating compound. For these compounds, reference should be madeto J. Photopolym. Sci. and Tech., 8, 43–44, 45–46 (1995), and ibid., 9,29–30 (1996).

Examples of the acid-propagating compound includetert-butyl-2-methyl-2-tosyloxymethyl acetoacetate and2-phenyl-2-(2-tosyloxyethyl)-1,3-dioxolane, but are not limited thereto.Of well-known photoacid generators, many of those compounds having poorstability, especially poor thermal stability exhibit an acid-propagatingcompound-like behavior.

In the resist composition comprising the sulfonyldiazomethane as thephotoacid generator according to the invention, an appropriate amount ofthe acid-propagating compound is up to 2 parts, and especially up to 1part by weight per 100 parts by weight of the solids in the composition.Excessive amounts of the acid-propagating compound make diffusioncontrol difficult, leading to degradation of resolution and patternconfiguration.

Component (D)

The basic compound used as component (D) is preferably a compoundcapable of suppressing the rate of diffusion when the acid generated bythe photoacid generator diffuses within the resist film. The inclusionof this type of basic compound holds down the rate of acid diffusionwithin the resist film, resulting in better resolution. In addition, itsuppresses changes in sensitivity following exposure and reducessubstrate and environment dependence, as well as improving the exposurelatitude and the pattern profile.

Examples of basic compounds include primary, secondary, and tertiaryaliphatic amines, mixed amines, aromatic amines, heterocyclic amines,carboxyl group-bearing nitrogenous compounds, sulfonyl group-bearingnitrogenous compounds, hydroxyl group-bearing nitrogenous compounds,hydroxyphenyl group-bearing nitrogenous compounds, alcoholic nitrogenouscompounds, amide derivatives, and imide derivatives.

Examples of suitable primary aliphatic amines include ammonia,methylamine, ethylamine, n-propylamine, isopropylamine, n-butylamine,isobutylamine, sec-butylamine, tert-butylamine, pentylamine,tert-amylamine, cyclopentylamine, hexylamine, cyclohexylamine,heptylamine, octylamine, nonylamine, decylamine, dodecylamine,cetylamine, methylenediamine, ethylenediamine, andtetraethylenepentamine. Examples of suitable secondary aliphatic aminesinclude dimethylamine, diethylamine, di-n-propylamine, diisopropylamine,di-n-butylamine, diisobutylamine, di-sec-butylamine, dipentylamine,dicyclopentylamine, dihexylamine, dicyclohexylamine, diheptylamine,dioctylamine, dinonylamine, didecylamine, didodecylamine, dicetylamine,N,N-dimethylmethylenediamine, N,N-dimethylethylenediamine, andN,N-dimethyltetraethylenepentamine. Examples of suitable tertiaryaliphatic amines include trimethylamine, triethylamine,tri-n-propylamine, triisopropylamine, tri-n-butylamine,triisobutylamine, tri-sec-butylamine, tripentylamine,tricyclopentylamine, trihexylamine, tricyclohexylamine, triheptylamine,trioctylamine, trinonylamine, tridecylamine, tridodecylamine,tricetylamine, N,N,N′,N′-tetramethylmethylenediamine,N,N,N′,N′-tetramethylethylenediamine, andN,N,N′,N′-tetramethyltetraethylenepentamine.

Examples of suitable mixed amines include dimethylethylamine,methylethylpropylamine, benzylamine, phenethylamine, andbenzyldimethylamine. Examples of suitable aromatic and heterocyclicamines include aniline derivatives (e.g., aniline, N-methylaniline,N-ethylaniline, N-propylaniline, N,N-dimethylaniline, 2-methylaniline,3-methylaniline, 4-methylaniline, ethylaniline, propylaniline,trimethylaniline, 2-nitroaniline, 3-nitroaniline, 4-nitroaniline,2,4-dinitroaniline, 2,6-dinitroaniline, 3,5-dinitroaniline, andN,N-dimethyltoluidine), diphenyl(p-tolyl)amine, methyldiphenylamine,triphenylamine, phenylenediamine, naphthylamine, diaminonaphthalene,pyrrole derivatives (e.g., pyrrole, 2H-pyrrole, 1-methylpyrrole,2,4-dimethylpyrrole, 2,5-dimethylpyrrole, and N-methylpyrrole), oxazolederivatives (e.g., oxazole and isooxazole), thiazole derivatives (e.g.,thiazole and isothiazole), imidazole derivatives (e.g., imidazole,4-methylimidazole, and 4-methyl-2-phenylimidazole), pyrazolederivatives, furazan derivatives, pyrroline derivatives (e.g., pyrrolineand 2-methyl-1-pyrroline), pyrrolidine derivatives (e.g., pyrrolidine,N-methylpyrrolidine, pyrrolidinone, and N-methylpyrrolidone),imidazoline derivatives, imidazolidine derivatives, pyridine derivatives(e.g., pyridine, methylpyridine, ethylpyridine, propylpyridine,butylpyridine, 4-(1-butylpentyl)pyridine, dimethylpyridine,trimethylpyridine, triethylpyridine, phenylpyridine,3-methyl-2-phenylpyridine, 4-tert-butylpyridine, diphenylpyridine,benzylpyridine, methoxypyridine, butoxypyridine, dimethoxypyridine,1-methyl-2-pyridone, 4-pyrrolidinopyridine, 1-methyl-4-phenylpyridine,2-(1-ethylpropyl)pyridine, aminopyridine, and dimethylaminopyridine),pyridazine derivatives, pyrimidine derivatives, pyrazine derivatives,pyrazoline derivatives, pyrazolidine derivatives, piperidinederivatives, piperazine derivatives, morpholine derivatives, indolederivatives, isoindole derivatives, 1H-indazole derivatives, indolinederivatives, quinoline derivatives (e.g., quinoline and3-quinolinecarbonitrile), isoquinoline derivatives, cinnolinederivatives, quinazoline derivatives, quinoxaline derivatives,phthalazine derivatives, purine derivatives, pteridine derivatives,carbazole derivatives, phenanthridine derivatives, acridine derivatives,phenazine derivatives, 1,10-phenanthroline derivatives, adeninederivatives, adenosine derivatives, guanine derivatives, guanosinederivatives, uracil derivatives, and uridine derivatives.

Examples of suitable carboxyl group-bearing nitrogenous compoundsinclude aminobenzoic acid, indolecarboxylic acid, and amino acidderivatives (e.g. nicotinic acid, alanine, arginine, aspartic acid,glutamic acid, glycine, histidine, isoleucine, glycylleucine, leucine,methionine, phenylalanine, threonine, lysine,3-aminopyrazine-2-carboxylic acid, and methoxyalanine). Examples ofsuitable sulfonyl group-bearing nitrogenous compounds include3-pyridinesulfonic acid and pyridinium p-toluenesulfonate. Examples ofsuitable hydroxyl group-bearing nitrogenous compounds, hydroxyphenylgroup-bearing nitrogenous compounds, and alcoholic nitrogenous compoundsinclude 2-hydroxypyridine, aminocresol, 2,4-quinolinediol,3-indolemethanol hydrate, monoethanolamine, diethanolamine,triethanolamine, N-ethyldiethanolamine, N,N-diethylethanolamine,trilsopropanolamine, 2,2′iminodiethanol, 2-aminoethanol,3-amino-1-propanol, 4-amino-1-butanol, 4-(2-hydroxyethyl)morpholine,2-(2-hydroxyethyl)pyridine, 1-(2-hydroxyethyl)piperazine,1-[2-(2-hydroxyethoxy)ethyl]piperazine, piperidine ethanol,1-(2-hydroxyethyl)pyrrolidine, 1-(2-hydroxyethyl)-2-pyrrolidinone,3-piperidino-1,2-propanediol, 3-pyrrolidino-1,2-propanediol,8-hydroxyjulolidine, 3-quinuclidinol, 3-tropanol, 1-methyl-2-pyrrolidineethanol, 1-aziridine ethanol, N-(2-hydroxyethyl)phthalimide, andN-(2-hydroxyethyl)isonicotinamide. Examples of suitable amidederivatives include formamide, N-methylformamide, N,N-dimethylformamide,acetamide, N-methylacetamide, N,N-dimethylacetamide, propionamide, andbenzamide. Suitable imide derivatives include phthalimide, succinimide,and maleimide.

In addition, basic compounds of the following general formula (D1) mayalso be included alone or in admixture.N(X′)_(w)(Y)_(3-w)  (D1)

In the formula, w is equal to 1, 2 or 3; Y is independently hydrogen ora straight, branched or cyclic alkyl group of 1 to 20 carbon atoms whichmay contain a hydroxyl group or ether structure; and X′ is independentlyselected from groups of the following general formulas (X′1) to (X′3),and two or three X′ may bond together to form a ring.

In the formulas, R³⁰⁰, R³⁰² and R³⁰⁵ are independently straight orbranched alkylene groups of 1 to 4 carbon atoms; R³⁰¹, R³⁰⁴ and R³⁰⁶ areindependently hydrogen, straight, branched or cyclic alkyl groups of 1to 20 carbon atoms, which may contain at least one hydroxyl group, etherstructure, ester structure or lactone ring; and R³⁰³ is a single bond ora straight or branched alkylene group of 1 to 4 carbon atoms.

Illustrative examples of the basic compounds of formula (D1) includetris(2-methoxymethoxyethyl)amine, tris{2-(2-methoxyethoxy)ethyl}amine,tris{2-(2-methoxyethoxymethoxy)ethyl}amine,tris{2-(1-methoxyethoxy)ethyl}amine, tris{2-(1-ethoxyethoxy)ethyl}amine,tris{2-(1-ethoxypropoxy)ethyl}amine,tris[2-{2-(2-hydroxyethoxy)ethoxy}ethyl]amine,4,7,13,16,21,24-hexaoxa-1,10-diazabicyclo[8.8.8]hexacosane,4,7,13,18-tetraoxa-1,10-diazabicyclo[8.5.5]eicosane,1,4,10,13-tetraoxa-7,16-diazabicyclooctadecane,1-aza-12-crown-4,1-aza-15-crown-5,1-aza-18-crown-6,tris(2-formyloxyethyl)amine, tris(2-acetoxyethyl)amine,tris(2-propionyloxyethyl)amine, tris(2-butyryloxyethyl)amine,tris(2-isobutyryloxyethyl)amine, tris(2-valeryloxyethyl)amine,tris(2-pivaloyloxyethyl)amine,N,N-bis(2-acetoxyethyl)-2-(acetoxyacetoxy)ethylamine,tris(2-methoxycarbonyloxyethyl)amine,tris(2-tert-butoxycarbonyloxyethyl)amine,tris[2-(2-oxopropoxy)ethyl]amine,tris[2-(methoxycarbonylmethyl)oxyethyl]amine,tris[2-(tert-butoxycarbonylmethyloxy)ethyl]amine,tris[2-(cyclohexyloxycarbonylmethyloxy)ethyl]amine,tris(2-methoxycarbonylethyl)amine, tris(2-ethoxycarbonylethyl)amine,N,N-bis(2-hydroxyethyl)-2-(methoxycarbonyl)ethylamine,N,N-bis(2-acetoxyethyl)-2-(methoxycarbonyl)ethylamine,N,N-bis(2-hydroxyethyl)-2-(ethoxycarbonyl)ethylamine,N,N-bis(2-acetoxyethyl)-2-(ethoxycarbonyl)ethylamine,N,N-bis(2-hydroxyethyl)-2-(2-methoxyethoxycarbonyl)ethylamine,N,N-bis(2-acetoxyethyl)-2-(2-methoxyethoxycarbonyl)ethylamine,N,N-bis(2-hydroxyethyl)-2-(2-hydroxyethoxycarbonyl)ethylamine,N,N-bis(2-acetoxyethyl)-2-(2-acetoxyethoxycarbonyl)ethylamine,N,N-bis(2-hydroxyethyl)-2-[(methoxycarbonyl)methoxycarbonyl]ethylamine,N,N-bis(2-acetoxyethyl)-2-[(methoxycarbonyl)methoxycarbonyl]ethylamine,N,N-bis(2-hydroxyethyl)-2-(2-oxopropoxycarbonyl)ethylamine,N,N-bis(2-acetoxyethyl)-2-(2-oxopropoxycarbonyl)ethylamine,N,N-bis(2-hydroxyethyl)-2-(tetrahydrofurfuryloxycarbonyl)ethylamine,N,N-bis(2-acetoxyethyl)-2-(tetrahydrofurfuryloxycarbonyl)ethylamine,N,N-bis(2-hydroxyethyl)-2-[(2-oxotetrahydrofuran-3-yl)oxycarbonyl]ethylamine,N,N-bis(2-acetoxyethyl)-2-[(2-oxotetrahydrofuran-3-yl)oxycarbonyl]ethylamine,N,N-bis(2-hydroxyethyl)-2-(4-hydroxybutoxycarbonyl)ethylamine,N,N-bis(2-formyloxyethyl)-2-(4-formyloxybutoxycarbonyl)ethylamine,N,N-bis(2-formyloxyethyl)-2-(2-formyloxyethoxycarbonyl)ethylamine,N,N-bis(2-methoxyethyl)-2-(methoxycarbonyl)ethylamine,N-(2-hydroxyethyl)-bis[2-(methoxycarbonyl)ethyl]amine,N-(2-acetoxyethyl)-bis[2-(methoxycarbonyl)ethyl]amine,N-(2-hydroxyethyl)-bis[2-(ethoxycarbonyl)ethyl]amine,N-(2-acetoxyethyl)-bis[2-(ethoxycarbonyl)ethyl]amine,N-(3-hydroxy-1-propyl)-bis[2-(methoxycarbonyl)ethyl]amine,N-(3-acetoxy-1-propyl)-bis[2-(methoxycarbonyl)ethyl]amine,N-(2-methoxyethyl)-bis[2-(methoxycarbonyl)ethyl]amine,N-butyl-bis[2-(methoxycarbonyl)ethyl]amine,N-butyl-bis[2-(2-methoxyethoxycarbonyl)ethyl]amine,N-methyl-bis(2-acetoxyethyl)amine, N-ethyl-bis(2-acetoxyethyl)amine,N-methyl-bis(2-pivaloyloxyethyl)amine,N-ethyl-bis[2-(methoxycarbonyloxy)ethyl]amine,N-ethyl-bis[2-(tert-butoxycarbonyloxy)ethyl]amine,tris(methoxycarbonylmethyl)amine, tris(ethoxycarbonylmethyl)amine,N-butyl-bis(methoxycarbonylmethyl)amine,N-hexyl-bis(methoxycarbonylmethyl)amine, andβ-(diethylamino)-δ-valerolactone.

Also useful are one or more of cyclic structure-bearing basic compoundshaving the following general formula (D2).

Herein X′ is as defined above, and R³⁰⁷ is a straight or branchedalkylene group of 2 to 20 carbon atoms which may contain one or morecarbonyl groups, ether structures, ester structures or sulfidestructures.

Illustrative examples of the cyclic structure-bearing basic compoundshaving formula (D2) include 1-[2-(methoxymethoxy)ethyl]pyrrolidine,1-[2-(methoxymethoxy)ethyl]piperidine,4-[2-(methoxymethoxy)ethyl]morpholine,1-[2-[(2-methoxyethoxy)methoxy]ethyl]pyrrolidine,1-[2-[(2-methoxyethoxy)methoxy]ethyl]piperidine,4-[2-[(2-methoxyethoxy)methoxy]ethyl]morpholine, 2-(1-pyrrolidinyl)ethylacetate, 2-piperidinoethyl acetate, 2-morpholinoethyl acetate,2-(1-pyrrolidinyl)ethyl formate, 2-piperidinoethyl propionate,2-morpholinoethyl acetoxyacetate, 2-(1-pyrrolidinyl)ethylmethoxyacetate, 4-[2-(methoxycarbonyloxy)ethyl]morpholine,1-[2-(t-butoxycarbonyloxy)ethyl]piperidine,4-[2-(2-methoxyethoxycarbonyloxy)ethyl]morpholine, methyl3-(1-pyrrolidinyl)propionate, methyl 3-piperidinopropionate, methyl3-morpholinopropionate, methyl 3-(thiomorpholino)propionate, methyl2-methyl-3-(1-pyrrolidinyl)propionate, ethyl 3-morpholinopropionate,methoxycarbonylmethyl 3-piperidinopropionate, 2-hydroxyethyl3-(1-pyrrolidinyl)propionate, 2-acetoxyethyl 3-morpholinopropionate,2-oxotetrahydrofuran-3-yl 3-(1-pyrrolidinyl)propionate,tetrahydrofurfuryl 3-morpholinopropionate, glycidyl3-piperidinopropionate, 2-methoxyethyl 3-morpholinopropionate,2-(2-methoxyethoxy)ethyl 3-(1-pyrrolidinyl)propionate, butyl3-morpholinopropionate, cyclohexyl 3-piperidinopropionate,α-(1-pyrrolidinyl)methyl-γ-butyrolactone, β-piperidino-γ-butyrolactone,β-morpholino-δ-valerolactone, methyl 1-pyrrolidinylacetate, methylpiperidinoacetate, methyl morpholinoacetate, methylthiomorpholinoacetate, ethyl 1-pyrrolidinylacetate, and 2-methoxyethylmorpholinoacetate.

Also, one or more of cyano-bearing basic compounds having the followinggeneral formulae (D3) to (D6) may be blended.

Herein, X′, R³⁰⁷ and w are as defined above, and R³⁰⁸ and R³⁰⁹ are eachindependently a straight or branched alkylene group of 1 to 4 carbonatoms.

Illustrative examples of the cyano-bearing basic compounds havingformulae (D3) to (D6) include 3-(diethylamino)propiononitrile,N,N-bis(2-hydroxyethyl)-3-aminopropiononitrile,N,N-bis(2-acetoxyethyl)-3-aminopropiononitrile,N,N-bis(2-formyloxyethyl)-3-aminopropiononitrile,N,N-bis(2-methoxyethyl)-3-aminopropiononitrile,N,N-bis[2-(methoxymethoxy)ethyl]-3-aminopropiononitrile, methylN-(2-cyanoethyl)-N-(2-methoxyethyl)-3-aminopropionate, methylN-(2-cyanoethyl)-N-(2-hydroxyethyl)-3-aminopropionate, methylN-(2-acetoxyethyl)-N-(2-cyanoethyl)-3-aminopropionate,N-(2-cyanoethyl)-N-ethyl-3-aminopropiononitrile,N-(2-cyanoethyl)-N-(2-hydroxyethyl)-3-aminopropiononitrile,N-(2-acetoxyethyl)-N-(2-cyanoethyl)-3-aminopropiononitrile,N-(2-cyanoethyl)-N-(2-formyloxyethyl)-3-aminopropiononitrile,N-(2-cyanoethyl)-N-(2-methoxyethyl)-3-aminopropiononitrile,N-(2-cyanoethyl)-N-[2-(methoxymethoxy)ethyl]-3-aminopropiononitrile,N-(2-cyanoethyl)-N-(3-hydroxy-1-propyl)-3-aminopropiononitrile,N-(3-acetoxy-1-propyl)-N-(2-cyanoethyl)-3-aminopropiononitrile,N-(2-cyanoethyl)-N-(3-formyloxy-1-propyl)-3-aminopropiononitrile,N-(2-cyanoethyl)-N-tetrahydrofurfuryl-3-aminopropiononitrile,N,N-bis(2-cyanoethyl)-3-aminopropiononitrile, diethylaminoacetonitrile,N,N-bis(2-hydroxyethyl)aminoacetonitrile,N,N-bis(2-acetoxyethyl)aminoacetonitrile,N,N-bis(2-formyloxyethyl)aminoacetonitrile,N,N-bis(2-methoxyethyl)aminoacetonitrile,N,N-bis[2-(methoxymethoxy)ethyl]aminoacetonitrile, methylN-cyanomethyl-N-(2-methoxyethyl)-3-aminopropionate, methylN-cyanomethyl-N-(2-hydroxyethyl)-3-aminopropionate, methylN-(2-acetoxyethyl)-N-cyanomethyl-3-aminopropionate,N-cyanomethyl-N-(2-hydroxyethyl)aminoacetonitrile,N-(2-acetoxyethyl)-N-(cyanomethyl)aminoacetonitrile,N-cyanomethyl-N-(2-formyloxyethyl)aminoacetonitrile,N-cyanomethyl-N-(2-methoxyethyl)aminoacetonitrile,N-cyanomethyl-N-[2-(methoxymethoxy)ethyl)aminoacetonitrile,N-cyanomethyl-N-(3-hydroxy-1-propyl)aminoacetonitrile,N-(3-acetoxy-1-propyl)-N-(cyanomethyl)aminoacetonitrile,N-cyanomethyl-N-(3-formyloxy-1-propyl)aminoacetonitrile,N,N-bis(cyanomethyl)aminoacetonitrile, 1-pyrrolidinepropiononitrile,1-piperidinepropiononitrile, 4-morpholinepropiononitrile,1-pyrrolidineacetonitrile, 1-piperidineacetonitrile,4-morpholineacetonitrile, cyanomethyl 3-diethylaminopropionate,cyanomethyl N,N-bis(2-hydroxyethyl)-3-aminopropionate, cyanomethylN,N-bis(2-acetoxyethyl)-3-aminopropionate, cyanomethylN,N-bis(2-formyloxyethyl)-3-aminopropionate, cyanomethylN,N-bis(2-methoxyethyl)-3-aminopropionate, cyanomethylN,N-bis[2-(methoxymethoxy)ethyl]-3-aminopropionate, 2-cyanoethyl3-diethylaminopropionate, 2-cyanoethylN,N-bis(2-hydroxyethyl)-3-aminopropionate, 2-cyanoethylN,N-bis(2-acetoxyethyl)-3-aminopropionate, 2-cyanoethylN,N-bis(2-formyloxyethyl)-3-aminopropionate, 2-cyanoethylN,N-bis(2-methoxyethyl)-3-aminopropionate, 2-cyanoethylN,N-bis[2-(methoxymethoxy)ethyl]-3-aminopropionate, cyanomethyl1-pyrrolidinepropionate, cyanomethyl 1-piperidinepropionate, cyanomethyl4-morpholinepropionate, 2-cyanoethyl 1-pyrrolidinepropionate,2-cyanoethyl 1-piperidinepropionate, and 2-cyanoethyl4-morpholinepropionate.

The basic compounds may be used alone or in admixture of two or more.The basic compound is preferably formulated in an amount of 0 to 2parts, and especially 0.01 to 1 part by weight, per 100 parts by weightof the solids in the resist composition. The use of more than 2 parts ofthe basis compound would result in too low a sensitivity.

Component (E)

Illustrative, non-limiting, examples of the organic acid derivatives (E)include phenol, cresol, catechol, resorcinol, pyrogallol, fluoroglycin,bis(4-hydroxyphenyl)methane, 2,2-bis(4′-hydroxyphenyl)propane,bis(4-hydroxyphenyl)sulfone, 1,1,1-tris(4′-hydroxyphenyl)ethane,1,1,2-tris(4′-hydroxyphenyl)ethane, hydroxybenzophenone,4-hydroxyphenylacetic acid, 3-hydroxyphenylacetic acid,2-hydroxyphenylacetic acid, 3-(4-hydroxyphenyl)propionic acid,3-(2-hydroxyphenyl)propionic acid, 2,5-dihydroxyphenylacetic acid,3,4-dihydroxyphenylacetic acid, 1,2-phenylenediacetic acid,1,3-phenylenediacetic acid, 1,4-phenylenediacetic acid,1,2-phenylenedioxydiacetic acid, 1,4-phenylenedipropanoic acid, benzoicacid, salicylic acid, 4,4-bis(4′-hydroxyphenyl)valeric acid,4-tert-butoxyphenylacetic acid, 4-(4-hydroxyphenyl)butyric acid,3,4-dihydroxymandelic acid, and 4-hydroxymandelic acid. Of these,salicylic acid and 4,4-bis(4′-hydroxyphenyl)valeric acid are preferred.They may be used alone or in admixture of two or more.

In the resist composition comprising the sulfonyldiazomethane as thephotoacid generator according to the invention, the organic acidderivative is preferably formulated in an amount of up to 5 parts, andespecially up to 1 part by weight, per 100 parts by weight of the solidsin the resist composition. The use of more than 5 parts of the organicacid derivative would result in too low a resolution. Depending on thecombination of the other components in the resist composition, theorganic acid derivative may be omitted.

Component (F)

Component (F) is an organic solvent. Illustrative, non-limiting,examples include butyl acetate, amyl acetate, cyclohexyl acetate,3-methoxybutyl acetate, methyl ethyl ketone, methyl amyl ketone,cyclohexanone, cyclopentanone, 3-ethoxyethyl propionate, 3-ethoxymethylpropionate, 3-methoxymethyl propionate, methyl acetoacetate, ethylacetoacetate, diacetone alcohol, methylpyruvate, ethyl pyruvate,propylene glycol monomethyl ether, propylene glycol monoethyl ether,propylene glycol monomethyl ether propionate, propylene glycol monoethylether propionate, ethylene glycol monomethyl ether, ethylene glycolmonoethyl ether, diethylene glycol monomethyl ether, diethylene glycolmonoethyl ether, 3-methyl-3-methoxybutanol, N-methylpyrrolidone,dimethyl sulfoxide, γ-butyrolactone, propylene glycol methyl etheracetate, propylene glycol ethyl ether acetate, propylene glycol propylether acetate, methyl lactate, ethyl lactate, propyl lactate, andtetramethylsulfonic acid. Of these, the propylene glycol alkyl etheracetates and alkyl lactates are especially preferred. The solvents maybe used alone or in admixture of two or more. An exemplary usefulsolvent mixture is a mixture of a propylene glycol alkyl ether acetateand an alkyl lactate. It is noted that the alkyl groups of the propyleneglycol alkyl ether acetates are preferably those of 1 to 4 carbon atoms,for example, methyl, ethyl and propyl, with methyl and ethyl beingespecially preferred. Since the propylene glycol alkyl ether acetatesinclude 1,2- and 1,3-substituted ones, each includes three isomersdepending on the combination of substituted positions, which may be usedalone or in admixture.

When the propylene glycol alkyl ether acetate is used as the solvent, itpreferably accounts for at least 50% by weight of the entire solvent.Also when the alkyl lactate is used as the solvent, it preferablyaccounts for at least 50% by weight of the entire solvent. When amixture of propylene glycol alkyl ether acetate and alkyl lactate isused as the solvent, that mixture preferably accounts for at least 50%by weight of the entire solvent. In this solvent mixture, it is furtherpreferred that the propylene glycol alkyl ether acetate is 60 to 95% byweight and the alkyl lactate is 40 to 5% by weight. A lower proportionof the propylene glycol alkyl ether acetate would invite a problem ofinefficient coating whereas a higher proportion thereof would provideinsufficient dissolution and allow for particle and foreign matterformation. A lower proportion of the alkyl lactate would provideinsufficient dissolution and cause the problem of many particles andforeign matter whereas a higher proportion thereof would lead to acomposition which has a too high viscosity to apply and loses storagestability.

The solvent is preferably used in an amount of 300 to 2,000 parts byweight, especially 400 to 1,000 parts by weight per 100 parts by weightof the solids in the resist composition. The solvent concentration isnot limited thereto as long as a film can be formed by existing methods.

Component (G)

In one preferred embodiment, the resist composition further contains (G)a compound with a molecular weight of up to 3,000 which changes itssolubility in an alkaline developer under the action of an acid, thatis, a dissolution inhibitor. Typically, a compound obtained by partiallyor entirely substituting acid labile substituents on a phenol orcarboxylic acid derivative having a molecular weight of up to 2,500 isadded as the dissolution inhibitor.

Examples of the phenol or carboxylic acid derivative having a molecularweight of up to 2,500 include bisphenol A, bisphenol H, bisphenol S,4,4-bis(4′-hydroxyphenyl)valeric acid, tris(4-hydroxyphenyl)methane,1,1,1-tris(4′-hydroxyphenyl)ethane, 1,1,2-tris(4′-hydroxyphenyl)ethane,phenolphthalein, and thymolphthalein. The acid labile substituents arethe same as those exemplified as the acid labile groups in the polymer.

Illustrative, non-limiting, examples of the dissolution inhibitors whichare useful herein include

-   bis(4-(2′-tetrahydropyranyloxy)phenyl)methane,-   bis(4-(2′-tetrahydrofuranyloxy)phenyl)methane,-   bis(4-tert-butoxyphenyl)methane,-   bis(4-tert-butoxycarbonyloxyphenyl)methane,-   bis(4-tert-butoxycarbonylmethyloxyphenyl)methane,-   bis(4-(1′-ethoxyethoxy)phenyl)methane,-   bis(4-(1′-ethoxypropyloxy)phenyl)methane,-   2,2-bis(4′-(2″-tetrahydropyranyloxy))propane,-   2,2-bis(4′-(2″-tetrahydrofuranyloxy)phenyl)propane,-   2,2-bis(4′-tert-butoxyphenyl)propane,-   2,2-bis(4′-tert-butoxycarbonyloxyphenyl)propane,-   2,2-bis(4-tert-butoxycarbonylmethyloxyphenyl)propane,-   2,2-bis(4′-(1″-ethoxyethoxy)phenyl)propane,-   2,2-bis(4′-(1″-ethoxypropyloxy)phenyl)propane,-   tert-butyl 4,4-bis(4′-(2″-tetrahydropyranyloxy)phenyl)valerate,-   tert-butyl 4,4-bis(4′-(2″-tetrahydrofuranyloxy)phenyl)valerate,-   tert-butyl 4,4-bis(4′-tert-butoxyphenyl)valerate,-   tert-butyl 4,4-bis(4-tert-butoxycarbonyloxyphenyl)valerate,-   tert-butyl 4,4-bis(4′-tert-butoxycarbonylmethyloxyphenyl)valerate,-   tert-butyl 4,4-bis(4′-(1″-ethoxyethoxy)phenyl)valerate,-   tert-butyl 4,4-bis(4′-(1″-ethoxypropyloxy)phenyl)valerate,-   tris(4-(2′-tetrahydropyranyloxy)phenyl)methane,-   tris(4-(2′-tetrahydrofuranyloxy)phenyl)methane,-   tris(4-tert-butoxyphenyl)methane,-   tris(4-tert-butoxycarbonyloxyphenyl)methane,-   tris(4-tert-butoxycarbonyloxymethylphenyl)methane,-   tris(4-(1′-ethoxyethoxy)phenyl)methane,-   tris(4-(1′-ethoxypropyloxy)phenyl)methane,-   1,1,2-tris(4′-(2″-tetrahydropyranyloxy)phenyl)ethane,-   1,1,2-tris(4′-(2″-tetrahydrofuranyloxy)phenyl)ethane,-   1,1,2-tris(4′-tert-butoxyphenyl)ethane,-   1,1,2-tris(4′-tert-butoxycarbonyloxyphenyl)ethane,-   1,1,2-tris(4′-tert-butoxycarbonylmethyloxyphenyl)ethane,-   1,1,2-tris(4′-(1′-ethoxyethoxy)phenyl)ethane, and-   1,1,2-tris(4′-(1′-ethoxypropyloxy)phenyl)ethane.

In the resist composition comprising the sulfonyldiazomethane of formula(1) or (1a) as the photoacid generator according to the invention, anappropriate amount of the dissolution inhibitor is up to 20 parts, andespecially up to 15 parts by weight per 100 parts by weight of thesolids in the resist composition. With more than 20 parts of thedissolution inhibitor, the resist composition becomes less heatresistant because of an increased content of monomer components.

Component (H)

In a chemical amplification, negative working, resist composition aswell, the sulfonyldiazomethane of formula (1) or (1a) according to theinvention may be used as the photoacid generator. This compositionfurther contains an alkali-soluble resin as component (H), examples ofwhich are intermediates of the above-described component (A) though notlimited thereto. Examples of the alkali-soluble resin includepoly(p-hydroxystyrene), poly(m-hydroxystyrene),poly(4-hydroxy-2-methylstyrene), poly(4-hydroxy-3-methylstyrene),poly(α-methyl-p-hydroxystyrene),

partially hydrogenated p-hydroxystyrene copolymers,p-hydroxystyrene-α-methyl-p-hydroxystyrene copolymers,p-hydroxystyrene-α-methylstyrene copolymers, p-hydroxystyrene-styrenecopolymers, p-hydroxystyrene-m-hydroxystyrene copolymers,p-hydroxystyrene-styrene copolymers, p-hydroxystyrene-acrylic acidcopolymers, p-hydroxystyrene-methacrylic acid copolymers,p-hydroxystyrene-methyl methacrylate copolymers,p-hydroxystyrene-acrylic acid-methyl methacrylate copolymers,p-hydroxystyrene-methyl acrylate copolymers,p-hydroxystyrene-methacrylic acid-methyl methacrylate copolymers,poly(methacrylic acid), poly(acrylic acid), acrylic acid-methyl acrylatecopolymers, methacrylic acid-methyl methacrylate copolymers, acrylicacid-maleimide copolymers, methacrylic acid-maleimide copolymers,p-hydroxystyrene-acrylic acid-maleimide copolymers, andp-hydroxystyrene-methacrylic acid-maleimide copolymers, but are notlimited to these combinations.

Preferred are poly(p-hydroxystyrene), partially hydrogenatedp-hydroxystyrene copolymers, p-hydroxystyrene-styrene copolymers,p-hydroxystyrene-acrylic acid copolymers, andp-hydroxystyrene-methacrylic acid copolymers.

Alkali-soluble resins comprising units of the following formula (2),(2′), (2″) or (2″′) are especially preferred.

Herein R⁴ is hydrogen or methyl; and R⁵ is a straight, branched orcyclic alkyl group of 1 to 8 carbon atoms. The subscript x is 0 or apositive integer; y is a positive integer, satisfying x+y≦5, yy is 0 ora positive integer, satisfying x+yy≦5; M and N are positive integers,satisfying 0<N/(M+N)≦0.5; A and B are positive integers, C is 0 or apositive integer, satisfying 0<B/(A+B+C)≦0.5, ZZ is a divalent groupselected from among CH₂, CH(OH), CR⁵(OH), C═O and C(OR⁵)(OH), or atrivalent organic group represented by —C(OH)═; F is independently apositive integer, and H is a positive integer, satisfying0.001≦H/(H+F)≦0.1; and XX is 1 or 2.

The polymer should preferably have a weight average molecular weight(Mw) of 3,000 to 100,000. Many polymers with Mw of less than 3,000 donot perform well and are poor in heat resistance and film formation.Many polymers with Mw of more than 100,000 give rise to a problem withrespect to dissolution in the resist solvent and developer. The polymershould also preferably have a dispersity (Mw/Mn) of up to 3.5, and morepreferably up to 1.5. With a dispersity of more than 3.5, resolution islow in many cases. Although the preparation method is not critical, apoly(p-hydroxystyrene) or similar polymer with a low dispersity ornarrow dispersion can be synthesized by living anion polymerization.

To impart a certain function, suitable substituent groups may beintroduced into some of the phenolic hydroxyl and carboxyl groups on theforegoing polymer. Exemplary and preferred are substituent groups forimproving adhesion to the substrate, substituent groups for improvingetching resistance, and especially substituent groups which arerelatively stable against acid and alkali and effective for controllingsuch that the dissolution rate in an alkali developer of unexposed andlow exposed areas of a resist film may not become too high.Illustrative, non-limiting, substituent groups include 2-hydroxyethyl,2-hydroxypropyl, methoxymethyl, methoxycarbonyl, ethoxycarbonyl,methoxycarbonylmethyl, ethoxycarbonylmethyl, 4-methyl-2-oxo-4-oxolanyl,4-methyl-2-oxo-4-oxanyl, methyl, ethyl, n-propyl, isopropyl, n-butyl,sec-butyl, acetyl, pivaloyl, adamantyl, isobornyl, and cyclohexyl. It isalso possible to introduce acid-decomposable substituent groups such ast-butoxycarbonyl and relatively acid-undecomposable substituent groupssuch as t-butyl and t-butoxycarbonylmethyl.

In the resist composition, the above resin is blended in any desiredamount, preferably of 65 to 99 parts by weight, especially 70 to 98parts by weight per 100 parts by weight of the solids.

Also contained in the negative resist composition is (I) an acidcrosslinking agent capable of forming a crosslinked structure under theaction of an acid. Typical acid crosslinking agents are compounds havingat least two hydroxymethyl, alkoxymethyl, epoxy or vinyl ether groups ina molecule. Substituted glycoluril derivatives, urea derivatives, andhexa(methoxymethyl)melamine compounds are suitable as the acidcrosslinking agent in the chemically amplified, negative resistcomposition comprising the sulfonyldiazomethane. Examples includeN,N,N′,N′-tetramethoxymethylurea, hexamethoxymethylmelamine,tetraalkoxymethyl-substituted glycoluril compounds such astetrahydroxymethyl-substituted glycoluril andtetramethoxymethylglycoluril, and condensates of phenolic compounds suchas substituted or unsubstituted bis(hydroxymethylphenol) compounds andbisphenol A with epichlorohydrin. Especially preferred acid crosslinkingagents are 1,3,5,7-tetraalkoxymethylglycolurils such as1,3,5,7-tetramethoxymethylglycoluril,1,3,5,7-tetrahydroxymethylglycoluril, 2,6-dihydroxymethyl-p-cresol,2,6-dihydroxymethylphenol, 2,2′,6,6′-tetrahydroxymethyl-bisphenol A,1,4-bis[2-(2-hydroxypropyl)]benzene, N,N,N′,N′-tetramethoxymethylurea,and hexamethoxymethylmelamine.

An appropriate amount of the acid crosslinking agent is, but not limitedthereto, about 1 to 20 parts, and especially about 5 to 15 parts byweight per 100 parts by weight of the solids in the resist composition.The acid crosslinking agents may be used alone or in admixture of any.

Component (J) is an alkali-soluble compound having a molecular weight ofup to 2,500. Any suitable compound may be used although a compoundhaving at least two phenol and/or carboxyl groups is preferred.Illustrative, non-limiting, examples of the alkali-soluble compound (J)include cresol, catechol, resorcinol, pyrogallol, fluoroglycin,bis(4-hydroxyphenyl)methane, 2,2-bis(4′-hydroxyphenyl)propane,bis(4-hydroxyphenyl)sulfone, 1,1,1-tris(4′-hydroxyphenyl)ethane,1,1,2-tris(4′-hydroxyphenyl)ethane, hydroxybenzophenone,4-hydroxyphenylacetic acid, 3-hydroxyphenylacetic acid,2-hydroxyphenylacetic acid, 3-(4-hydroxyphenyl)propionic acid,3-(2-hydroxyphenyl)propionic acid, 2,5-dihydroxyphenylacetic acid,3,4-dihydroxyphenylacetic acid, 1,2-phenylenediacetic acid,1,3-phenylenediacetic acid, 1,4-phenylenediacetic acid,1,2-phenylenedioxydiacetic acid, 1,4-phenylenedipropanoic acid, benzoicacid, salicylic acid, 4,4-bis(4′-hydroxyphenyl)valeric acid,4-tert-butoxyphenylacetic acid, 4-(4-hydroxyphenyl)butyric acid,3,4-dihydroxymandelic acid, and 4-hydroxymandelic acid. Of these,salicylic acid and 4,4-bis(4′-hydroxyphenyl)valeric acid are preferred.They may be used alone or in admixture of two or more. Thealkali-soluble compound is blended in any desired amount, preferably of0 to 20 parts by weight, especially 2 to 10 parts by weight per 100parts by weight of the solids in the resist composition.

In the chemical amplification type resist composition according to theinvention, there may be added such additives as a surfactant forimproving coating, and a light absorbing agent for reducing diffusereflection from the substrate.

Illustrative, non-limiting, examples of the surfactant include nonionicsurfactants, for example, polyoxyethylene alkyl ethers such aspolyoxyethylene lauryl ether, polyoxyethylene stearyl ether,polyoxyethylene cetyl ether, and polyoxyethylene oleyl ether,polyoxyethylene alkylaryl ethers such as polyoxyethylene octylphenolether and polyoxyethylene nonylphenol ether, polyoxyethylenepolyoxypropylene block copolymers, sorbitan fatty acid esters such assorbitan monolaurate, sorbitan monopalmitate, and sorbitan monostearate,and polyoxyethylene sorbitan fatty acid esters such as polyoxyethylenesorbitan monolaurate, polyoxyethylene sorbitan monopalmitate,polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitantrioleate, and polyoxyethylene sorbitan tristearate; fluorochemicalsurfactants such as EFTOP EF301, EF303 and EF352 (Tohkem Products Co.,Ltd.), Megaface F171, F172 and F173 (Dainippon Ink & Chemicals, Inc.),Fluorad FC430 and FC431 (Sumitomo 3M Co., Ltd.), Aashiguard AG710,Surflon S-381, S-382, SC101, SC102, SC103, SC104, SC105, SC106, SurfynolE1004, KH-10, KH-20, KH-30 and KH-40 (Asahi Glass Co., Ltd.);organosiloxane polymers KP341, X-70-092 and X-70-093 (Shin-Etsu ChemicalCo., Ltd.), acrylic acid or methacrylic acid Polyflow No. 75 and No. 95(Kyoeisha Ushi Kagaku Kogyo K.K.). Inter alia, FC430, Surflon S-381,Surfynol E1004, KH-20 and KH-30 are preferred. These surfactants may beused alone or in admixture.

In the chemical amplification type resist composition according to theinvention, the surfactant is preferably formulated in an amount of up to2 parts, and especially up to 1 part by weight, per 100 parts by weightof the solids in the resist composition.

In the chemical amplification type resist composition according to theinvention, a UV absorber may be added. Those UV absorbers described inJP-A 11-190904 are useful, but the invention is not limited thereto.Exemplary UV absorbers are diaryl sulfoxide derivatives such asbis(4-hydroxyphenyl)sulfoxide, bis(4-tert-butoxyphenyl)sulfoxide,bis(4-tert-butoxycarbonyloxyphenyl)sulfoxide, andbis[4-(1-ethoxyethoxy)phenyl]sulfoxide; diarylsulfone derivatives suchas bis(4-hydroxyphenyl)sulfone, bis(4-tert-butoxyphenyl)sulfone,bis(4-tert-butoxycarbonyloxyphenyl)sulfone,bis[4-(1-ethoxyethoxy)phenyl]sulfone, andbis[4-(1-ethoxypropoxy)phenyl]sulfone; diazo compounds such asbenzoquinonediazide, naphthoquinonediazide, anthraquinonediazide,diazofluorene, diazotetralone, and diazophenanthrone; quinonediazidegroup-containing compounds such as complete or partial ester compoundsbetween naphthoquinone-1,2-diazide-5-sulfonic acid chloride and2,3,4-trihydroxybenzophenone and complete or partial ester compoundsbetween naphthoquinone-1,2-diazide-4-sulfonic acid chloride and2,4,4′-trihydroxybenzophenone; tert-butyl 9-anthracenecarboxylate,tert-amyl 9-anthracenecarboxylate, tert-methoxymethyl9-anthracenecarboxylate, tert-ethoxyethyl 9-anthracenecarboxylate,2-tert-tetrahydropyranyl 9-anthracenecarboxylate, and2-tert-tetrahydrofuranyl 9-anthracenecarboxylate. The UV absorber may ormay not be added to the resist composition depending on the type ofresist composition. An appropriate amount of UV absorber, if added, is 0to 10 parts, more preferably 0.5 to 10 parts, most preferably 1 to 5parts by weight per 100 parts by weight of the base resin.

For the microfabrication of integrated circuits, any well-knownlithography may be used to form a resist pattern from the chemicalamplification type resist composition comprising thesulfonyldiazomethane photoacid generator of formula (1) or (1a) and theresin which changes solubility in an alkaline developer under the actionof acid according to the invention.

The composition is applied onto a substrate (e.g., Si, SiO₂, SiN, SiON,TiN, WSi, BPSG, SOG, organic anti-reflecting film, etc.) by a suitablecoating technique such as spin coating, roll coating, flow coating, dipcoating, spray coating or doctor coating. The coating is prebaked on ahot plate at a temperature of 60 to 150° C. for about 1 to 10 minutes,preferably 80 to 120° C. for 1 to 5 minutes. The resulting resist filmis generally 0.1 to 2.0 μm thick. With a mask having a desired patternplaced above the resist film, the resist film is then exposed to actinicradiation, preferably having an exposure wavelength of up to 300 nm,such as UV, deep-UV, electron beams, x-rays, excimer laser light, γ-raysand synchrotron radiation in an exposure dose of about 1 to 200 mJ/cm²,preferably about 10 to 100 mJ/cm². The film is further baked on a hotplate at 60 to 150° C. for 1 to 5 minutes, preferably 80 to 120° C. for1 to 3 minutes (post-exposure baking=PEB).

Thereafter the resist film is developed with a developer in the form ofan aqueous base solution, for example, 0.1 to 5%, preferably 2 to 3%aqueous solution of tetramethylammonium hydroxide (TMAH) for 0.1 to 3minutes, preferably 0.5 to 2 minutes by conventional techniques such asdipping, puddling or spraying. In this way, a desired resist pattern isformed on the substrate. It is appreciated that the resist compositionof the invention is best suited for micro-patterning using such actinicradiation as deep UV with a wavelength of 254 to 193 nm, vacuum UV witha wavelength of 157 nm, electron beams, x-rays, excimer laser light,γ-rays and synchrotron radiation. With any of the above-describedparameters outside the above-described range, the process may sometimesfail to produce the desired pattern.

EXAMPLE

Examples of the invention are given below by way of illustration and notby way of limitation.

Synthesis Example 1

Synthesis of 2-(n-hexyloxy)-5-tert-butylthiophenol

In 158 g of ethanol were dissolved 105 g (0.7 mol) of 4-tert-butylphenoland 30.8 g (0.77 mol) of sodium hydroxide. To the solution at 70° C.,127 g (0.77 mol) of n-bromohexane was added dropwise. The solution wasallowed to ripen for 4 hours and cooled to room temperature, after which158 g of water was added. The oily phase was separated therefrom andconcentrated on a rotary evaporator, yielding 167 g of an oily matter.Then 167 g of the oily matter was dissolved in 600 g of dichloromethane.While cooling in an ice/water bath, 100 g (0.625 mol) of bromine wasadded dropwise at a temperature below 10° C. After the completion ofdropwise addition, 300 g of water was added. The organic layer wasseparated and washed with a saturated sodium hydrogen carbonate aqueoussolution. The organic layer was concentrated on a rotary evaporator,yielding 208 g of an oily matter. On analysis by gas chromatography/massanalysis and gas chromatography, the oily matter was found to contain90% of 2-bromo-4-tert-butyl-1-n-hexyloxybenzene.

Using 208 g (0.60 mol) of the 2-bromo-4-tert-butyl-1-n-hexyloxybenzene(90% pure), 15.4 g (0.63 mol) of metallic magnesium and 450 g oftetrahydrofuran, a Grignard reagent was prepared in a conventionalmanner. The Grignard reagent was ice cooled, to which 18.3 g (0.57 mol)of colloidal sulfur was added at a temperature below 20° C. The solutionwas allowed to ripen for 2 hours at room temperature, then ice cooledagain. To the solution, 90 g of conc. hydrochloric acid (12N) and 300 gof water were added. The organic layer was separated and concentrated ona rotary evaporator, yielding 180 g of an oily matter. This concentratewas distilled in vacuum (boiling point 132–135° C./0.5 Torr), obtaining115 g of the end compound, 2-(n-hexyloxy)-5-tert-butylthiophenol with apurity of 90% (yield 64%).

Synthesis Example 2

Synthesis of bis(2-(n-hexyloxy)-5-tert-butylbenzenesulfonyl)methane

In 230 g of ethanol were dissolved 115 g (0.39 mol) of the above2-(n-hexyloxy)-5-tert-butylthiophenol and 16.4 g (0.41 mol) of sodiumhydroxide. Then 23.1 g (0.27 mol) of dichloromethane was added dropwiseat a temperature below 50° C. The solution was heated on an oil bath to60° C. and allowed to ripen at the temperature for 3 hours. The solutionwas allowed to cool down to room temperature, after which 420 g of waterand 300 g of dichloromethane were added. The organic layer was separatedand the solvent was removed by means of a rotary evaporator, yielding124 g of formaldehyde bis(2-(n-hexyloxy)-5-tert-butylbenzenethio)acetal.

To 400 g of acetonitrile were added 124 g of the formaldehydebis(2-(n-hexyloxy)-5-tert-butylbenzenethio)acetal and 1.9 g (0.0058 mol)of sodium tungstate. The solution was heated on an oil bath to 70° C.Then 94 g (0.97 mol) of 35% aqueous hydrogen peroxide was added dropwiseat a temperature below 75° C. The solution was held at the temperaturefor 4 hours and then cooled on an ice bath whereupon white crystalsprecipitated. The crystals were filtered, collecting 95 g (yield 80%) ofthe end bis(2-(n-hexyloxy)-5-tert-butylbenzenesulfonyl)methane.

Synthesis Example 3

Synthesis of bis(2-(n-hexyloxy)-5-tert-butylbenzenesulfonyl)diazomethane

In 120 g of dichloromethane were dissolved 12.1 g (0.02 mol) of theabove bis(2-(n-hexyloxy)-5-tert-butylbenzenesulfonyl)methane and 5.9 g(0.03 mol) of p-toluenesulfonylazide. The solution was cooled on an icebath, and 3.0 g (0.02 mol) of 1,8-diazabicyclo[5.4.0]-7-undecene (DBU)was added at a temperature below 5° C. The solution was allowed to ripenat room temperature for 2 hour, after which 100 g of water was added.The organic layer was separated and washed with 100 g of water, afterwhich the solvent was removed by means of a rotary evaporator, obtaining35 g of an oily matter. It was purified by silica gel columnchromatography (eluent: dichloromethane), obtaining 4.5 g (yield 35%) ofthe end compound,bis(2-(n-hexyloxy)-5-tert-butylbenzenesulfonyl)diazomethane.

The thus obtainedbis(2-(n-hexyloxy)-5-tert-butylbenzenesulfonyl)diazomethane was analyzedby nuclear magnetic resonance (NMR) spectroscopy, infrared (IR)absorption spectroscopy and thermogravimetric analysis (Tdec), with theresults shown below.

¹H-NMR: CDCl₃ (ppm) (1) Ha 0.887–0.934 triplet  6H (2) Hb, Hc 1.30–1.40multiplet  8H (3) Hi 1.296 singlet 18H (4) Hd 1.430–1.527 multiplet  4H(5) He 1.812–1.908 multiplet  4H (6) Hf 4.051–4.096 triplet  4H (7) Hg6.878–6.907 doublet  2H (8) Hh 7.510–7.547 quadruplet  2H (9) Hj7.800–7.808 doublet  2H

-   IR (cm⁻¹): 2960, 2873, 2859, 2121, 1497, 1466, 1365, 1350, 1336,    1294, 1269, 1169, 1149, 1066, 982, 829, 673, 594, 580, 552-   Thermogravimetric analysis: 146.6° C. (the temperature at which a    weight change of −0.1 wt % occurred upon heating at a rate of 10°    C./min from room temperature)

Synthesis Example 4

Synthesis of 2-(n-hexyloxy)-5-methylthiophenol

In 92 g of ethanol were dissolved 46.7 g (0.25 mol) of2-bromo-4-methylphenol and 11.0 g (0.275 mol) of sodium hydroxide. Tothe solution at 70° C., 45.4 g (0.275 mol) of n-bromohexane was addeddropwise. The solution was allowed to ripen for 4 hours and cooled toroom temperature, after which 190 g of water was added. The oily phasewas separated therefrom and concentrated on a rotary evaporator,yielding 67 g of an oily matter. On analysis by gas chromatography/massanalysis and gas chromatography, the oily matter was found to contain95% of 2-bromo-4-tert-butyl-1-n-hexyloxybenzene.

Using 67 g (0.235 mol) of the 2-bromo-4-tert-butyl-1-n-hexyloxybenzene(95% pure), 6.1 g (0.25 mol) of metallic magnesium and 163 g oftetrahydrofuran, a Grignard reagent was prepared in a conventionalmanner. The Grignard reagent was ice cooled, to which 7.45 g (0.23 mol)of colloidal sulfur was added at a temperature below 20° C. The solutionwas allowed to ripen for 2 hours at room temperature, then ice cooledagain. To the solution, 38 g of conc. hydrochloric acid (12N) and 125 gof water were added. The organic layer was separated and concentrated ona rotary evaporator, yielding 54 g of an oily matter. This concentratewas distilled in vacuum (boiling point 120–128° C./0.5 Torr), obtaining39 g of the end compound, 2-(n-hexyloxy)-5-methylthiophenol with apurity of 97% (yield 70%).

Synthesis Example 5

Synthesis of bis(2-(n-hexyloxy)-5-methylbenzenesulfonyl)methane

In 80 g of ethanol were dissolved 39 g (0.167 mol) of the above2-(n-hexyloxy)-5-methylthiophenol and 7.0 g (0.175 mol) of sodiumhydroxide. Then 9.9 g (0.117 mol) of dichloromethane was added dropwiseat a temperature below 50° C. The solution was heated on an oil bath to60° C. and allowed to ripen at the temperature for 3 hours. The solutionwas allowed to cool down to room temperature, after which 160 g of waterand 200 g of dichloromethane were added. The organic layer was separatedand the solvent was removed by means of a rotary evaporator, yielding 42g of formaldehyde bis(2-(n-hexyloxy)-5-methylbenzenethio)acetal.

To 156 g of acetonitrile were added 42 g of the formaldehydebis(2-(n-hexyloxy)-5-methylbenzenethio)acetal and 0.8 g (0.0025 mol) ofsodium tungstate. The solution was heated on an oil bath to 70° C. Then40.5 g (0.417 mol) of 35% aqueous hydrogen peroxide was added dropwiseat a temperature below 75° C. The solution was held at the temperaturefor 4 hours and then cooled on an ice bath whereupon white crystalsprecipitated. The crystals were filtered, collecting 40 g (yield 91%) ofthe end bis(2-(n-hexyloxy)-5-methylbenzenesulfonyl)methane.

Synthesis Example 6

Synthesis of bis(2-(n-hexyloxy)-5-methylbenzenesulfonyl)diazomethane

In 100 g of dichloromethane were dissolved 10.0 g (0.019 mol) of theabove bis(2-(n-hexyloxy)-5-methylbenzenesulfonyl)methane and 5.6 g(0.0285 mol) of p-toluenesulfonylazide. The solution was cooled on anice bath, and 2.89 g (0.019 mol) of 1,8-diazabicyclo[5.4.0]-7-undecene(DBU) was added at a temperature below 5° C. The solution was allowed toripen at room temperature for 2 hour, after which 100 g of water wasadded. The organic layer was separated and washed with 100 g of water,after which the solvent was removed by means of a rotary evaporator,obtaining 20 g of an oily matter. It was purified by silica gel columnchromatography (eluent: dichloromethane), obtaining 7.4 g (yield 71%) ofthe end compound,bis(2-(n-hexyloxy)-5-methylbenzenesulfonyl)diazomethane. It was analyzedby NMR, IR and thermogravimetric analysis, with the results shown below.

¹H-NMR: CDCl₃ (ppm) (1) Ha 0.883–0.930 triplet 6H (2) Hb, Hc 1.274–1.40 multiplet 8H (3) Hd  1.40–1.512 multiplet 4H (4) He 1.797–1.893multiplet 4H (5) Hi 2.275 singlet 6H (6) Hf 3.992–4.037 triplet 4H (7)Hg 6.761–6.790 doublet 2H (8) Hh 7.242–7.279 quadruplet 2H (9) Hj7.540–7.549 quadruplet 2H

-   IR (cm⁻¹): 2954, 2931, 2129, 1610, 1570, 1498, 1464, 1392, 1344,    1331, 1286, 1255, 1232, 1143, 1065, 993, 889, 823, 723, 694, 646,    598, 588, 569, 540-   Thermogravimetric analysis: 148° C. (the temperature at which a    weight change of −0.1 wt % occurred upon heating at a rate of 10°    C./min from room temperature)

Synthesis Example 7

20 Synthesis of bis(2-(n-hexyloxy)-5-ethylbenzenesulfonyl)diazomethane

The end compound, bis(2-(n-hexyloxy)-5-ethylbenzenesulfonyl)diazomethanewas synthesized as in Synthesis Examples 1 to 3 except that4-ethylphenol was used instead of 4-tert-butylphenol in SynthesisExample 1. The results of NMR, IR and thermogravimetric analyses areshown below.

¹H-NMR: CDCl₃ (ppm)  (1) Ha 0.883–0.930 triplet 6H  (2) Hk 1.165–1.215triplet 6H  (3) Hb, Hc 1.292–1.40  multiplet 8H  (4) Hd  1.40–1.515multiplet 4H  (5) He 1.801–1.896 multiplet 4H  (6) Hi 2.540–2.616quadruplet 4H  (7) Hf 4.003–4.048 triplet 4H  (8) Hg 6.798–6.826 doublet2H  (9) Hh 7.274–7.309 quadruplet 2H (10) Hj 7.567–7.575 doublet 2H

-   IR (cm⁻¹): 2951, 2869, 2129, 1608, 1498, 1461, 1344, 1330, 1228,    1255, 1230, 1141, 1062, 993, 937, 835, 692, 646, 588, 555, 522-   Thermogravimetric analysis: 141° C. (the temperature at which a    weight change of −0.1 wt % occurred upon heating at a rate of 10°    C./min from room temperature)

Synthesis Example 8

Synthesis of bis(2-(n-hexyloxy)-5-isopropylbenzenesulfonyl)diazomethane

The end compound,bis(2-(n-hexyloxy)-5-isopropylbenzenesulfonyl)diazomethane wassynthesized as in Synthesis Examples 1 to 3 except that4-isopropylphenol was used instead of 4-tert-butylphenol in SynthesisExample 1. The results of NMR, IR and thermogravimetric analyses areshown below.

¹H-NMR: CDCl₃ (ppm)  (1) Ha 0.885–0.931 triplet  6H  (2) Hk 1.203–1.226doublet 12H  (3) Hb, Hc 1.30–1.40 multiplet  8H  (4) Hd  1.40–1.518multiplet  4H  (5) He 1.804–1.900 multiplet  4H  (6) Hi 2.798–2.937multiplet  2H  (7) Hf 4.022–4.068 triplet  4H  (8) Hg 6.840–6.868doublet  2H  (9) Hh 7.331–7.368 quadruplet  2H (10) Hj 7.617–7.625doublet  2H

-   IR (cm⁻¹): 2958, 2931, 2871, 2127, 1606, 1494, 1465, 1344, 1330,    1290, 1255, 1162, 1143, 1062, 991, 833, 727, 680, 651, 586, 553-   Thermogravimetric analysis: 143° C. (the temperature at which a    weight change of −0.1 wt % occurred upon heating at a rate of 10°    C./min from room temperature)

Synthesis Example 9

Synthesis ofbis(2-(n-hexyloxy)-5-(2-methoxyethyl)benzenesulfonyl)diazomethane

The end compound,bis(2-(n-hexyloxy)-5-(2-methoxyethyl)benzenesulfonyl)diazomethane wassynthesized as in Synthesis Examples 1 to 3 except that4-(2-methoxyethyl)phenol was used instead of 4-tert-butylphenol inSynthesis Example 1. The results of NMR, IR and thermogravimetricanalyses are shown below.

¹H-NMR: CDCl₃ (ppm)  (1) Ha 0.880–0.926 triplet 6H  (2) Hb, Hc 1.28–1.40multiplet 8H  (3) Hd  1.40–1.513 multiplet 4H  (4) He 1.801–1.896multiplet 4H  (5) Hi 2.791–2.837 triplet 4H  (6) Hl 3.329 singlet 6H (7) Hk 3.515–3.561 triplet 4H  (8) Hf 4.026–4.071 triplet 4H  (9) Hg6.831–6.859 doublet 2H (10) Hh 7.344–7.380 quadruplet 2H (11) Hj7.611–7.618 doublet 2H

-   IR (cm⁻¹): 2959, 2929, 2869, 2130, 1498, 1473, 1349, 1332, 1286,    1257, 1143, 1116, 1064, 987, 592, 580, 551-   Thermogravimetric analysis: 144° C. (the temperature at which a    weight change of −0.1 wt % occurred upon heating at a rate of 10°    C./min from room temperature)

Reference Synthesis Example 1

Synthesis of bis(4-methoxyphenylsulfonyl)diazomethane

As in Synthesis Examples 1 to 3, the end compound was synthesized from4-methoxythiphenol (Tokyo Kasei Kogyo Co., Ltd.). The result ofthermogravimetric analysis is shown below.

Thermogravimetric analysis: 128° C. (the temperature at which a weightchange of −0.1 wt % occurred upon heating at a rate of 10° C./min fromroom temperature)

Reference Synthesis Example 2

Synthesis of bis(4-methylphenylsulfonyl)diazomethane

As in Synthesis Examples 1 to 3, the end compound was synthesized from4-methylthiphenol (Tokyo Kasei Kogyo Co., Ltd.). The result ofthermogravimetric analysis is shown below.

-   Thermogravimetric analysis: 124° C. (the temperature at which a    weight change of −0.1 wt % occurred upon heating at a rate of 10°    C./min from room temperature)

Examples 1–24 and Comparative Examples 1–3

Resist materials were formulated in accordance with the formulationshown in Tables 1 to 3. The components used are shown below.

-   Polymer A: poly(p-hydroxystyrene) in which hydroxyl groups are    protected with 15 mol % of 1-ethoxyethyl groups and 15 mol % of    tert-butoxycarbonyl groups, having a weight average molecular weight    of 12,000.-   Polymer B: poly(p-hydroxystyrene) in which hydroxyl groups are    protected with 30 mol % of 1-ethoxyethyl groups, having a weight    average molecular weight of 12,000.-   Polymer C: poly(p-hydroxystyrene) in which hydroxyl groups are    protected with 25 mol % of 1-ethoxyethyl groups and crosslinked with    3 mol % of 1,2-propanediol divinyl ether, having a weight average    molecular weight of 13,000.-   Polymer D: poly(p-hydroxystyrene) in which hydroxyl groups are    protected with 28 mol % of tert-pentyl groups, having a weight    average molecular weight of 8,000.-   Polymer E: p-hydroxystyrene/2-ethyl-2-adamantyl acrylate copolymer    having a compositional ratio (molar ratio) of 70:30 and a weight    average molecular weight of 15,000.-   Polymer F: p-hydroxystyrene/1-ethyl-1-norbornene methacrylate    copolymer having a compositional ratio (molar ratio) of 70:30 and a    weight average molecular weight of 15,000.-   Polymer G: p-hydroxystyrene/tert-butyl acrylate copolymer having a    compositional ratio (molar ratio) of 65:35 and a weight average    molecular weight of 15,000.-   Polymer H: p-hydroxystyrene/1-ethylcyclopentyl methacrylate    copolymer having a compositional ratio (molar ratio) of 65:35 and a    weight average molecular weight of 15,000.-   Polymer I: p-hydroxystyrene/1-ethylcyclopentyl    methacrylate/p-tert-pentyloxystyrene copolymer having a    compositional ratio (molar ratio) of 70:8:22 and a weight average    molecular weight of 16,000.-   Polymer J: p-hydroxystyrene/1-ethylcyclopentyl methacrylate/styrene    copolymer having a compositional ratio (molar ratio) of 65:10:25 and    a weight average molecular weight of 12,000.-   Polymer K: p-hydroxystyrene/indene copolymer having a compositional    ratio (molar ratio) of 80:20 in which hydroxyl groups on the    hydroxystyrene are protected with 20 mol % of tert-butoxycarbonyl    groups, and having a weight average molecular weight of 10,000.-   Polymer L: p-hydroxystyrene/indene/2-ethyl-2-adamantyl methacrylate    copolymer having a compositional ratio (molar ratio) of 82:4:14 and    a weight average molecular weight of 8,000.-   Polymer M: p-hydroxystyrene/indene/1-ethyl-1-norbornene methacrylate    copolymer having a compositional ratio (molar ratio) of 84:4:12 and    a weight average molecular weight of 8,000.-   Polymer N: poly(p-hydroxystyrene) in which hydroxyl groups are    protected with 8 mol % of acetyl groups, having a weight average    molecular weight of 8,000.-   PAG1: compound of Synthesis Example 3-   PAG2: compound of Synthesis Example 6-   PAG3: compound of Synthesis Example 7-   PAG4: compound of Synthesis Example 8-   PAG5: (4-tert-butoxyphenyl)diphenylsulfonium 10-camphorsulfonate-   PAG6: bis(4-methoxyphenylsulfonyl)diazomethane-   PAG7: bis(cyclohexylsulfonyl)diazomethane-   PAG8: bis(4-methylphenylsulfonyl)diazomethane-   PAG9: N-10-camphorsulfonyloxysuccinimide-   Crosslinker A: 1,3,5,7-tetramethoxymethylglycoluril-   Dissolution inhibitor: bis(4-(2′-tetrahydropyranyloxy)phenyl)methane-   Basic compound A: tri(n-butyl)amine-   Basic compound B: tris(2-methoxyethyl)amine-   Organic acid derivative A: 4,4-bis(4′-hydroxyphenyl)valeric acid-   Organic acid derivative B: salicylic acid-   Surfactant A: FC-430 (Sumitomo 3M Co., Ltd.)-   Surfactant B: Surflon S-381 (Asahi Glass Co., Ltd.)-   UV absorber: 9,10-dimethylanthracene-   Solvent A: propylene glycol methyl ether acetate-   Solvent B: ethyl lactate

The resist materials thus obtained were each filtered through a 0.2-μmTeflon® filter, thereby giving resist solutions. These resist solutionswere spin-coated onto silicon wafers having an organic antireflectionfilm (DUV-44, Brewer Science) of 800 Å thick coated thereon, so as togive a dry thickness of 0.6 μm.

The coated wafer was then baked on a hot plate at 100° C. for 90seconds. The resist films were exposed to ⅔ annular illumination usingan excimer laser stepper NSR—S202A (Nikon Corporation, NA=0.6), thenbaked (PEB) at 110° C. for 90 seconds, and developed with a solution of2.38% tetramethylammonium hydroxide in water, thereby giving positivepatterns (Examples 1 to 23 and Comparative Examples 1–3) or negativepattern (Example 24).

The resulting resist patterns were evaluated as described below.

Resist Pattern Evaluation

The optimum exposure dose (sensitivity Eop) was the exposure dose whichprovided a 1:1 resolution at the top and bottom of a 0.18-μmline-and-space pattern. The minimum line width (μm) of a line-and-spacepattern which was ascertained separate at this dose was the resolutionof a test resist. The shape in cross section of the resolved resistpattern was examined under a scanning electron microscope. The depth offocus (DOF) was determined by offsetting the focal point and judging theresist to be satisfactory when the resist pattern shape was keptrectangular and the resist pattern film thickness was kept above 80% ofthat at accurate focusing.

The PED stability of a resist was evaluated by effecting post-exposurebake (PEB) after 24 hours of holding from exposure at the optimum doseand determining a variation in line width. The less the variation, thegreater is the PED stability.

The results of resist pattern evaluation are shown in Table 4.

Other Evaluation

The solubility of resist material in a solvent mixture was examined byvisual observation and in terms of clogging upon filtration.

With respect to the applicability of a resist solution, uneven coatingwas visually observed. Additionally, using an optical interference filmgage Lambda-Ace VM-3010 (Dainippon Screen Mfg. Co., Ltd.), the thicknessof a resist film on a common wafer was measured at different positions,based on which a variation from the desired coating thickness (0.6 μm)was calculated. The applicability was rated “good” when the variationwas within 0.5% (that is, within 0.003 μm), “unacceptable” when thevariation was within 1%, and “poor” when the variation was more than 1%.

Storage stability was judged in terms of foreign matter precipitation orsensitivity change with the passage of time. After the resist solutionwas aged for 100 days at the longest, the number of particles of 0.3 μmor larger per ml of the resist solution was counted by means of aparticle counter KL-20A (Rion Co., Ltd.). Also, a change with time ofsensitivity (Eop) from that immediately after preparation wasdetermined. The storage stability was rated “good” when the number ofparticles is not more than 5 or when the sensitivity change was within5%, and “poor” otherwise.

Debris appearing on the developed pattern was observed under a scanningelectron microscope (TDSEM) model S-7280H (Hitachi Ltd.). The resistfilm was rated “good” when the number of foreign particles was up to 10per 100 μm², “unacceptable” when from 11 to 15, and “poor” when morethan 15.

Debris left after resist peeling was examined using a surface scannerSurf-Scan 6220 (Tencol Instruments). A resist-coated 8-inch wafer wassubjected to entire exposure rather than patterned exposure, processedin a conventional manner, and developed with a 2.38% TMAH solutionbefore the resist film was peeled off (only the resist film in theexposed area was peeled). After the resist film was peeled, the waferwas examined and rated “good” when the number of foreign particles ofgreater than 0.20 μm was up to 100, “unacceptable” when from 101 to 150,and “poor” when more than 150.

The results are shown in Table 5.

TABLE 1 Composition Example (pbw) 1 2 3 4 5 6 7 8 9 10 11 12 Polymer A80 40 Polymer B 80 Polymer C 80 Polymer D 80 Polymer E 80 Polymer F 80Polymer G 80 Polymer H 80 Polymer I 80 Polymer J 80 Polymer K 80 PolymerL 80 Polymer M Polymer N PAG1 3 3 3 2 PAG2 3 2 3 3 PAG3 3 1 3 PAG4 2 2 2PAG5 1 1 1 2 PAG6 PAG7 1 1 2 2 1 1 PAG8 1 1 PAG9 Dissolution inhibitorBasic compound A 0.3 0.3 0.3 0.3 0.3 0.15 0.3 0.3 Basic compound B 0.150.3 0.3 0.3 0.3 Organic acid 0.5 0.5 0.5 derivative A Organic acid 0.5derivative B Surfactant A 0.25 0.25 0.25 0.25 0.25 0.25 Surfactant B0.25 0.25 0.25 0.25 0.25 0.25 UV absorber Solvent A 385 385 385 385 385385 385 280 382 385 280 385 Solvent B 105 105

TABLE 2 Composition Example (pbw) 13 14 15 16 17 18 19 20 21 22 23 24Polymer A 40 60 Polymer B 60 75 Polymer C 40 40 Polymer D 70 40 60 40Polymer E 40 10 Polymer F Polymer G 40 Polymer H Polymer I 10 20 PolymerJ Polymer K 40 Polymer L 40 20 70 Polymer M 40 20 Polymer N 80 PAG1 3 22 2 2 PAG2 2 2 2 2 PAG3 3 3 2 PAG4 2 2 2 PAG5 1 1 2 2 PAG6 0.5 0.5 PAG71.5 1.5 1 1 1 PAG8 0.5 PAG9 1 1 1 Crosslinker A 20 Dissolution 5inhibitor Basic compound A 0.15 0.3 0.3 0.3 Basic compound B 0.3 0.150.3 0.3 0.3 0.3 0.3 0.3 0.3 Organic acid 0.5 0.5 derivative A Organicacid 0.25 derivative B Surfactant A 0.25 0.25 0.25 0.25 0.25 0.25Surfactant B 0.25 0.25 0.25 0.25 0.25 UV absorber 0.5 Solvent A 280 385385 385 280 385 385 385 280 385 280 385 Solvent B 105 105 105 105

TABLE 3 Comparative Example Composition (pbw) 1 2 3 Polymer A 80 40Polymer E 80 Polymer K 40 PAG5 PAG6 2.5 PAG7 1 PAG8 2.5 2.5 PAG9 1Dissolution inhibitor Basic compound A 0.125 Basic compound B 0.1250.125 Organic acid derivative A 0.5 Organic acid derivative B SurfactantA 0.25 0.25 Surfactant B 0 0.25 UV absorber Solvent A 385 385 385Solvent B

TABLE 4 24 hr PED DOF at dimensional Sensitivity Resolution 0.18 μmOff-focus stability (mJ/cm²) (μm) Profile (μm) profile* (nm) Example 137 0.14 rectangular 1.0 rectangular −10 Example 2 41 0.14 rectangular1.0 rectangular 10 Example 3 36 0.14 rectangular 1.0 rectangular −8Example 4 35 0.14 rectangular 1.0 rectangular −8 Example 5 31 0.16rectangular 1.1 rectangular −8 Example 6 33 0.15 rectangular 1.0rectangular −10 Example 7 32 0.14 rectangular 1.1 rectangular −8 Example8 35 0.16 rectangular 1.1 rectangular −8 Example 9 33 0.14 rectangular1.1 rectangular −10 Example 10 39 0.15 rectangular 1.1 rectangular −10Example 11 31 0.16 rectangular 1.0 rectangular −9 Example 12 35 0.15rectangular 1.1 rectangular −10 Example 13 39 0.15 rectangular 1.0rectangular 10 Example 14 31 0.14 rectangular 1.1 rectangular −8 Example15 33 0.14 rectangular 1.1 rectangular −8 Example 16 35 0.15 rectangular1.0 rectangular −8 Example 17 33 0.14 rectangular 1.1 rectangular −10Example 18 39 0.14 rectangular 1.0 rectangular −8 Example 19 31 0.15rectangular 0.8 rectangular −10 Example 20 35 0.14 rectangular 1.0rectangular −8 Example 21 39 0.15 rectangular 1.0 rectangular −8 Example22 31 0.14 rectangular 1.0 rectangular −10 Example 23 33 0.14rectangular 1.1 rectangular −10 Example 24 32 0.18 rectangular 0.8rectangular −9 Comparative 25 0.15 forward 0.8 forward −10 Example 1taper taper Comparative 32 0.15 rounded 0.8 rounded −8 Example 2 headhead Comparative 35 0.15 forward 0.8 forward −10 Example 3 taper taper*the shape of a pattern obtained when the focus was shifted −0.4 μm tominus side upon DOF measurement at 0.18 μm

TABLE 5 100 day Debris after Debris after Dissolution Applicationstorage stability development resist peeling Example 1 good good goodgood good Example 2 good good good good good Example 3 good good goodgood good Example 4 good good good good good Example 5 good good goodgood good Example 6 good good good good good Example 7 good good goodgood good Example 8 good good good good good Example 9 good good goodgood good Example 10 good good good good good Example 11 good good goodgood good Example 12 good good good good good Example 13 good good goodgood good Example 14 good good good good good Example 15 good good goodgood good Example 16 good good good good good Example 17 good good goodgood good Example 18 good good good good good Example 19 good good goodgood good Example 20 good good good good good Example 21 good good goodgood good Example 22 good good good good good Example 23 good good goodgood good Example 24 good good good good good Comparative good good <30days poor unacceptable Example 1 (sensitivity changed) Comparative goodgood good unacceptable poor Example 2 Comparative good good good poorpoor Example 3

Examples 25–29 & Comparative Examples 4–6

Another experiment was performed by preparing resist solutions accordingto the formulation shown in Table 6 and baking resist coatings underdifferent conditions.

The resist materials were filtered through a 0.2-μm Teflon® filter,thereby giving resist solutions. The resist solutions were spin-coatedonto silicon wafers having an organic antireflection film (DUV-44,Brewer Science) of 800 Å thick coated thereon, so as to give a drythickness of 0.6 μm.

The coated wafers were then baked on a hot plate at 120° C. for 90seconds. The resist films were exposed to ⅔ annular illumination usingan excimer laser stepper NSR—S202A (Nikon Corporation, NA=0.6), thenbaked (PEB) at 130° C. for 90 seconds, and developed with a solution of2.38% tetramethylammonium hydroxide in water. It was examined whether ornot a pattern was formed. The results are shown in Table 7.

TABLE 6 Comparative Composition Example Example (pbw) 25 26 27 28 29 4 56 Polymer F 80 Polymer H 40 80 80 80 80 Polymer I 40 80 40 Polymer J 40PAG1 3 2 PAG2 3 1 PAG3 3 PAG4 3 PAG6 2 2 PAG7 2 PAG8 2 Dissolutioninhibitor Basic compound A 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 Basiccompound B Organic acid derivative A 0.5 Organic acid derivative BSurfactant A 0.25 0.25 0.25 Surfactant B 0.25 0.25 UV absorber Solvent A385 385 385 385 385 385 385 385 Solvent B

TABLE 7 Sensitivity Resolution (mJ/cm²) (μm) Profile Example 25 25 0.14rectangular Example 26 23 0.15 rectangular Example 27 24 0.15rectangular Example 28 24 0.14 rectangular Example 29 24 0.14rectangular Comparative Example 4  19**  0.20** rounded head ComparativeExample 5  17**  0.20** rounded head Comparative Example 6  18**  0.20**rounded head **0.18 μm unresolved; a sensitivity capable of resolving0.20 μm being reported

There have been described chemically amplified resist compositionscomprising a specific benzenesulfonyldiazomethane containing along-chain alkoxyl group at the 2-position on its benzene ring as thephotoacid generator. The compositions have many advantages includingimproved resolution, improved focus latitude, minimized line widthvariation or shape degradation even on long-term PED, thermal stability,minimized debris left after coating, development and peeling, andimproved pattern profile after development. Because of high resolution,the compositions are suited for microfabrication, especially by deep UVlithography.

Japanese Patent Application No. 2003-035077 is incorporated herein byreference.

Although some preferred embodiments have been described, manymodifications and variations may be made thereto in light of the aboveteachings. It is therefore to be understood that the invention may bepracticed otherwise than as specifically described without departingfrom the scope of the appended claims.

1. A sulfonyldiazomethane compound having the following general formula(1):

wherein R is each independently a substituted or unsubstituted straight,branched or cyclic alkyl group of 1 to 4 carbon atoms, G is SO₂ or CO,R³ is a substituted or unsubstituted straight, branched or cyclic alkylgroup of 1 to 10 carbon atoms or a substituted or unsubstituted arylgroup of 6 to 14 carbon atoms, p is 1 or 2, q is 0 or 1, satisfyingp+q=2, m is an integer of 3 to 11, and k is an integer of 0 to 4, withthe proviso that in the event k is at least 1, at least one of Rassociated with k may bond with the R at the 4-position to form a cyclicstructure with the carbon atoms on the benzene ring to which these R'sare attached, and then, these two R's bond together to form an alkylenegroup of 3 to 4 carbon atoms.
 2. A sulfonyldiazomethane compound havingthe following general formula (1a):

wherein R is each independently a substituted or unsubstituted straight,branched or cyclic alkyl group of 1 to 4 carbon atoms, and m is aninteger of 3 to
 11. 3. A photoacid generator for a chemicalamplification type resist composition comprising thesulfonyldiazomethane compound of claim
 1. 4. A chemical amplificationtype resist composition comprising (A) a resin which changes itssolubility in an alkaline developer under the action of an acid, and (B)the sulfonyldiazomethane compound of claim 1 which generates an acidupon exposure to radiation.
 5. A chemical amplification type resistcomposition comprising (A) a resin which changes its solubility in analkaline developer under the action of an acid, (B) thesulfonyldiazomethane compound of claim 1 which generates an acid uponexposure to radiation, and (C) a compound capable of generating an acidupon exposure to radiation, other than component (B).
 6. The resistcomposition of claim 4 wherein the resin (A) has such substituent groupshaving C—O—C linkages that the solubility in an alkaline developerchanges as a result of scission of the C—O—C linkages under the actionof an acid.
 7. The resist composition of claim 6 wherein the resin (A)is a polymer containing phenolic hydroxyl groups in which hydrogen atomsof the phenolic hydroxyl groups are substituted with acid labile groupsof one or more types in a proportion of more than 0 molt to 80 molt onthe average of the entire hydrogen atoms of the phenolic hydroxylgroups, the polymer having a weight average molecular weight of 3,000 to100,000.
 8. The resist composition of claim 7 wherein the resin (A) is apolymer comprising recurring units of the following general formula(2a):

wherein R⁴ is hydrogen or methyl, R⁵ is a straight, branched or cyclicalkyl group of 1 to 8 carbon atoms, x is 0 or a positive integer, y is apositive integer, satisfying x+y≦5, R⁶ is an acid labile group, S and Tare positive integers, satisfying 0<T/(S+T)≦0.8, wherein the polymercontains units in which hydrogen atoms of phenolic hydroxyl groups arepartially substituted with acid labile groups of one or more types, aproportion of the acid labile group-bearing units is on the average frommore than 0 mol % to 80 molt based on the entire polymer, and thepolymer has a weight average molecular weight of 3,000 to 100,000. 9.The resist composition of claim 6 wherein the resin (A) is a polymercomprising recurring units of the following general formula (2a′):

wherein R⁴ is hydrogen or methyl, R⁵ is a straight, branched or cyclicalkyl group of 1 to 8 carbon atoms, R⁶ is an acid labile group, R^(6a)is hydrogen or an acid labile group, at least some of R^(6a) being acidlabile groups, x is 0 or a positive integer, y is a positive integer,satisfying x+y≦5, M and N are positive integers, L is 0 or a positiveinteger, satisfying 0<N/(M+N+L)≦0.5 and 0<(N+L)/(M+N+L)≦0.8, wherein thepolymer contains on the average from more than 0 mol % to 50 mol % ofthose units derived from acrylate and methacrylate, and also contains onthe average from more than 0 mol % to 80 mol % of acid labilegroup-bearing units, based on the entire polymer, and the polymer has aweight average molecular weight of 3,000 to 100,000.
 10. The resistcomposition of claim 6 wherein the resin (A) is a polymer comprisingrecurring units of the following general formula (2a″):

wherein R⁴ is hydrogen or methyl, R⁵ is a straight, branched or cyclicalkyl group of 1 to 8 carbon atoms, R⁶ is an acid labile group, R^(6a)is hydrogen or an acid labile group, at least some of R^(6a) being acidlabile groups, x is 0 or a positive integer, y is a positive integer,satisfying x+y≦5, yy is 0 or a positive integer, satisfying x+yy≦5, Aand B are positive integers, C, D and E each are 0 or a positiveinteger, satisfying 0<(B+E)/(A+B+C+D+E)≦0.5 and0<(C+D+E)/(A+B+C+D+E)≦0.8, wherein the polymer contains on the averagefrom more than 0 mol % to 50 mol % of those units derived from indeneand/or substituted indene, and also contains on the average from morethan 0 mol % to 80 mol % of acid labile group-bearing units, based onthe entire polymer, and the polymer has a weight average molecularweight of 3,000 to 100,000.
 11. The resist composition of claim 7wherein the acid labile group is selected from the class consisting ofgroups of the following general formulae (4) to (7), tertiary alkylgroups of 4 to 20 carbon atoms, trialkylsilyl groups whose alkylmoieties each have 1 to 6 carbon atoms, oxoalkyl groups of 4 to 20carbon atoms, and aryl-substituted alkyl groups of 7 to 20 carbon atoms,

wherein R¹⁰ and R¹¹ each are hydrogen or a straight, branched or cyclicalkyl having 1 to 18 carbon atoms, and R¹² is a monovalent hydrocarbongroup of 1 to 18 carbon atoms which may contain a heteroatom, a pair ofR¹⁰ and R¹¹, R¹⁰ and R¹², or R¹¹ and R¹² may together form a ring, withthe proviso that R¹⁰, R¹¹, and R¹² each are a straight or branchedalkylene of 1 to 18 carbon atoms when they form a ring, R¹³ is atertiary alkyl group of 4 to 20 carbon atoms, a trialkysilyl group inwhich each of the alkyls has 1 to 6 carbon atoms, an oxoalkyl group of 4to 20 carbon atoms, or a group of the formula (4), z is an integer of 0to 6, R¹⁴ is a straight, branched or cyclic alkyl group of 1 to 8 carbonatoms or an aryl group of 6 to 20 carbon atoms which may be substituted,h is 0 or 1, i is 0, 1, 2 or 3, satisfying 2h+i=2 or 3, R¹⁵ is astraight, branched or cyclic alkyl group of 1 to 8 carbon atoms or anaryl group of 6 to 20 carbon atoms which may be substituted, R¹⁶ to R²⁵are each independently hydrogen or a monovalent hydrocarbon group of 1to 15 carbon atoms which may contain a heteroatom, any two of R¹⁶ toR²⁵, taken together, may form a ring, each of the ring-forming two ofR¹⁶ to R²⁵ is a divalent hydrocarbon group of 1 to 15 carbon atoms whichmay contain a heteroatom, or two of R¹⁶ to R²⁵ which are attached toadjoining carbon atoms may bond together directly to form a double bond.12. The resist composition of claim 4 further comprising (D) a basiccompound.
 13. The resist composition of claim 4 further comprising (E)an organic acid derivative.
 14. The resist composition of claim 4further comprising as an organic solvent a propylene glycol alkyl etheracetate, an alkyl lactate or a mixture thereof.
 15. A process forforming a pattern, comprising the steps of: applying the resistcomposition of claim 4 onto a substrate to form a coating, heat treatingthe coating and exposing the coating to high energy radiation with awavelength of up to 300 nm or electron beam through a photomask,optionally heat treating the exposed coating, and developing the coatingwith a developer.